Should I Modify My Car? (Pros, Cons, and Beginner Advice)

(Updated on October 18, 2022)

To some people, the vehicle you drive says as much about you as the clothes you wear. Automotive customization is a very personal thing, and there is no shortage of options in the aftermarket industry.

Have you ever tried shopping for a car that was almost perfect, but was missing that one feature you really want? Welcome to the world of car modifications.

You can make your car faster, louder, prettier, and even safer with the right modifications. Here is a crash course into the world of car modification, and some things you might want to consider if you plan on modifying yours.

What Is a Car Mod?

A car modification is any change to a vehicle that deviates from parts the vehicle was built with.

Car modifications may even include original equipment manufacturer (OEM) parts if they were sold on other trim levels or offered as accessories through a dealership.

What Mods Can I Do to My Car?

For every part you see on your car, there is at least one way to modify it. Your goals for the car will determine the best build path for you.

Cosmetic Mods

Some people stick to cosmetic mods like vinyl wraps, mud flaps, Plasti Dip, and window tint. These mods are often simple or inexpensive to apply. Some can easily be removed later if you change your mind or want to sell the car.

Some cosmetic mods also have practical benefits. For instance, window tint can block heat and light that would destroy the interior over time, and mud flaps can protect the body of the car from rock chips.

Competition, Racing, and Performance Mods

coilovers on BMW M3

Others are interested in road racing, HPDEs, hill climbs, time attack, and autocross. These people might start with wheels, brakes, tires, and suspension modifications, then move into cooling and aerodynamics mods as the build progresses.

These builds focus on grip, durability, and endurance to consistently turn the fastest lap times. Some high performance events require additional safety modifications, such as a six point harness, fixed back racing seats, roll bars, roll cages, and fire suppression systems.

Power Mods

dohc engine

Don’t like turns? No worries. There are plenty of people who want big power for quick times down a drag strip. These folks might add turbochargers or even perform engine swaps.

These builds prioritize power above all else, and often sacrifice reliability and streetability (how easy the car is to drive everyday) for raw power. You can turn just about any car into a 10 second car if your pockets are deep enough.

Is It Worth Modifying Your Car?

Modifying a car can cost substantial time and money, depending on what you’re trying to do. Every make and model has different aftermarket parts available. High quality parts and a vibrant enthusiast community make the installation process easier on certain models.

It is easy to find help if you get stuck when you’re working on a sporty car. Less people modify economy cars that are used mainly as appliances by the general population. Only you can decide if the process is worth it to you.

Pros

first time track day questions

Here are some of the benefits of modifying your car.

1) Your Car Will Be Completely Unique

Modifying your car gives you a chance to make your car uniquely yours. Although there were roughly 200,000 Subaru WRXs sold over the past generation, nobody else will have one with your exact combination of cosmetic and performance mods (unless you publish your build).

2) You Can Make a Cheap Car Really, Really Fast

Most people don’t have Ferrari money, but that doesn’t mean you can’t have Ferrari speed. If you’re willing to put in the work and do some research, many cars can be upgraded to be faster than exotic sports cars.

If you’re trying to build a performance machine, most of your expense will be labor rather than parts. When you have the space, tools, and knowledge to do the work yourself, the sky is the limit. An LS swapped Miata can make around 700 horsepower reliably in a car that weighs roughly 2,600 lbs.

3) Your Car Will Be Built for Your Interests

Most cars are set up from the factory to be quiet, comfortable, and livable every day. Some cars make compromises for compliance with California’s unique and very strict regulations.

Not everybody cares about a soft ride or a quiet cabin. If your goals are more performance oriented, there are a lot of changes you can make to a vehicle that will improve it for your specific use case.

For instance, you can buy a base model that comes with cheap wheels because you know you’re going to swap the wheels first thing anyway.

Cons

prevent engine overheating

Here are some things to consider before ditching factory parts.

1) May Reduce Reliability

Performance modifications often reduce reliability, particularly when you’ve changed any part of the engine (including the intake and the exhaust).

When you make more power than the vehicle was designed for, sometimes you run the risk of breaking other parts. These parts could be simple to fix like engine and transmission mounts, but they could be internal engine components such as piston rings and rod bearings.

Some vehicles require a piggyback ECU or aftermarket tune if you change any parts that would affect the air fuel ratio. Aftermarket tuning can typically only be done by a professional tuner. Modifying hard parts without the accompanying software is a recipe for disaster, and can quickly lead to a blown engine.

If the vehicle you want to modify is your daily driver, you may want to think twice before monkeying with the engine too much. Fixing or replacing an engine can take a considerable amount of time while you’re left without a vehicle. 

2) They’re Often Expensive

Aside from simple cosmetics, quality modifications are usually expensive. Expect to pay at least $1,000 for any substantial change to your vehicle’s performance. Many people have five or even six figures into the builds you see on YouTube.

Financing aftermarket modifications is usually not a wise idea. If you don’t have the funds to buy the parts outright (along with some extra in reserve in case something goes sideways), it may be best to save up some money so you have a bigger budget.

3) Some Mods Are Illegal

Depending on where you live, some changes to your vehicle might be illegal, or permitted for off-road use only. For instance, six point harnesses replace the stock seat belt and are often not DOT approved. Although they are suitable and very safe for racing applications, they are not street legal.

New Mexico lets you tint down to 20% on all side windows, even the front. In many other states, 35% is the lowest legal limit for front tint.

Aftermarket engine modifications are illegal in California unless they have been approved by the California Air Resource Board (CARB). This rules out a lot of options that are otherwise completely legal in other states.

Always check your local laws before modifying your vehicle. If you get pulled over, you may get a fix-it ticket asking you to revert the modification back to stock.

Easy Car Mods for Beginners

aftermarket wheels

1) Wheels and Tires

Wheels and tires are a quick and easy upgrade that will improve the look of your car. When you buy wheels and tires as a pre-mounted package from a store like Tire Rack, you can even swap them in your own driveway if you have a floor jack.

2) Aftermarket Stereo

Many infotainment systems are underpowered and don’t give the factory speakers enough output for good sound clarity. An upgrade to the aftermarket stereo often improves the sound quality in the cabin.

On older cars, this may also give you additional features such as Bluetooth and navigation.

3) Plasti Dip

Plasti Dip is a sprayable rubber coating that is easy to remove and instantly changes the color of just about anything. You can spray it on wheels, badges, plastic trim, or even the whole car. Plasti Dip comes in several different finishes including gloss, satin, and pearl.

Best Used Cars to Modify

The best used cars to modify are anything with an enthusiast following that was sold in high volume. These vehicles have the strongest aftermarket support, and the most options for quick bolt-on modifications.

Some examples of vehicles with excellent aftermarket support are the Jeep Wrangler, Toyota Tacoma, 4Runner, and 86, Ford Mustang, Focus, and Fiesta, Chevrolet Corvette, Camaro, and Silverado, Subaru BRZ and WRX, Nissan Z, Honda Civic, BMW 3 Series, Volkswagen Golf GTI, and the Mazda MX-5 Miata.

If you plan on modifying your car, it might be worthwhile to browse forums and Facebook groups to see what the community is like. This will give you a good indication of how other people build their cars and what options are out there.

What Modifications Increase Horsepower?

how to do a burnout in an automatic

Adding power is best done as a package, rather than a single upgraded part. Here are some examples of things you can do to give your car more horsepower.

1) Aftermarket Tune

Aftermarket tuning can be a quick way to pick up 20 to 50 horsepower, depending on how conservative the factory tune was. A good tuner will be able to squeeze a little bit of power out of factory parts, but at some point you will have to upgrade the hardware to flow more air and fuel.

2) Intake and Exhaust

muffler delete

Upgraded intake, headers, catalytic converter, and exhaust will open up restrictions and improve airflow. Since a combustion engine is just a fancy air pump, more air means more horsepower.

When you upgrade the intake and exhaust to increase airflow, you often have to upgrade injectors so the tuner can add more fuel. If you don’t tune to compensate for the increased airflow, some engines will run dangerously lean.

3) Switch to Premium (or E85)

Switching from regular to premium fuel and advancing the timing is often a quick and easy way to pick up a little power. This requires changes to engine tuning or advancing the distributor to realize the benefits of the increased octane rating.

E85 has an even higher octane rating than premium. It also has the added benefit of cooling the combustion chamber since more fuel is needed to maintain an ideal air fuel ratio. If E85 is available in your area, running this ethanol-based fuel can give you even greater performance benefits than premium would.

4) Forced Induction

boost gauge

Forced induction is the easiest way to add big power to any engine. If you slap a turbo or supercharger onto an engine, you’re able to shove a lot more air into that engine. This can easily compensate for smaller displacement, as long as the engine internals can handle the increased boost pressure.

If your engine is already turbocharged, you can also upgrade the intercooler to lower intake temperatures. Cooler air makes more power.

5) Engine Swaps

Adding a turbo to an engine often incurs a large reliability hit. Turbos increase heat, add a bunch of hoses, and put more stress on an engine that wasn’t designed for it. If you need reliable power, an engine swap should be your end goal.

LS swaps are probably the most popular engine swap, and many vehicles have engine swap kits that will allow you to replace the entire powertrain with minimal fabrication. Any swap is a very involved process and not something a novice should try to tackle on their own.

Modifications to Avoid

negative camber effects

Camrys with huge wings. Exhausts louder than your screaming children. Cars low enough to scrape on leaves. What in the Danger to Manifold were they thinking? Everyone has a different idea of what a tasteful car modification is.

Avoid modifications that alter the factory suspension geometry, unless the product has been tested thoroughly and solves a specific known problem with the factory setup. Modified suspension geometry could make the vehicle harder to handle and could cause an accident. Be careful with excessive negative camber on the street.

You should avoid any modification that compromises the safety of your vehicle, breaks local laws, or causes destruction to your engine or the environment. Don’t roll coal, and try not to be obnoxious to the people around you.

Do Mods Void My Warranty?

Some engine modifications could lead to a warranty claim being denied. In order for this to happen, the dealership or the manufacturer will likely need to show that the modification caused the failure.

That said, a warranty is not an “all or nothing” deal. Even if you wish to modify your engine, those changes shouldn’t affect your warranty for a recalled airbag or a bad headlight assembly. When you tint the windows, it won’t affect your powertrain warranty. Cosmetic modifications and catback exhausts are usually safe.

Each dealership is different, and some are less comfortable working on cars that have aftermarket parts installed. If you install an aftermarket downpipe that needs to be removed to replace a recalled part, some dealerships may refuse to work on your car.

If your vehicle is still under warranty, consider waiting to install performance modifications. This includes an aftermarket tune, which changes the programming of the ECU to alter engine performance. 

Should I Tell Insurance About My Modifications?

What mods need to be declared will depend on your individual insurance company. Read your insurance policy and note any clauses on performance modifications. Failing to disclose certain modifications may lead to insurance denying your claim.

If you have any doubt about which modifications you should disclose, ask your insurance company for more information.

Do Mods Increase the Value of a Car?

Generally speaking, aftermarket modifications do not increase the value of your car. In almost every case, you will be losing money by modifying your car if you choose to sell it later.

There are some rare instances where a build was completed by a performance shop using quality parts, and the car makes hundreds of horsepower more than it did when it left the factory. This will sometimes increase the value of the vehicle, but it’s generally not as much as you would’ve put into the build in the first place. You probably won’t get any labor costs back from the sale.

Conclusion

The possibilities are endless when it comes to modifying your vehicle. Think through your modification path and decide early on what your goals are. This will lead to the most seamless modification experience, and allow you to ask better questions on forums when you hit a roadblock during your build.

Have fun making your car unique!

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