The Best 4th Gen Subaru WRX Upgrades


The Subaru WRX is an absolute JDM icon. For decades, the rally racing icon has taken the tuner scene by storm. The Subaru WRX is seen at every car meet and is modified in a multitude of ways. When Subaru released the 4th generation WRX (2015-2021 model years), I loved the styling and what the car community was doing with them. The best part is that as a factory car, the WRX is set up pretty good out the gate. All-wheel drive, 268 horsepower, and a six-speed is a recipe for success. However, we know you aren’t trying to keep your Subaru WRX stock. In this article, we’re going to learn about the best 2015-2021 Subaru WRX upgrades and how to transform it into your perfect car!


Rather hear Alex break down the best Subaru WRX Upgrades? Check out his video!

What To Know About Upgrading a Subaru WRX 

A Turbocharged all-wheel drive rally monster is an appealing car for any enthusiast. Instantly, you’re going to want to crank up the boost, throw on some aftermarket wheels and tires, and slam that thing to the ground. I’m going to hit the pause button for you right there. I’m going to sound boring to you for a second, but I’m about to save your car and your bank account.

Reliability and Maintenance 

The internet is filled with memes about Subarus blowing up left and right. While it may sound like an exaggeration, all jokes have an ounce to truth. Modifying a Subaru WRX for sheer power is a recipe for an expensive disaster. The FA20 is a solid motor, but it will not give you any breaks for bad installs or tunes.

Oil consumption and oil burning are common concerns for this generation of WRX. Staying on top of a regular oil change service is going to be key to longevity. Also, consider upgrading the oil system with an oil catch can.

Boost-Related Issues 

The factory tune on the FA20 has some over-boost issues. Over-boost is when the PSI generated from your turbocharger spikes, causing it to have inconsistent boost levels. Your main priorities are going to be the diverter valve, intercooler, and your wastegate. Ensure these parts are all performing well and are leak free. Keep your car’s turbocharger running well and you’ll be prepped for your built!

So What Are The Best Subaru WRX Upgrades? 

Finally, we can get on to the reason you’re here: learning about the best Subaru WRX upgrades. Fortunately, your WRX has access to one of the biggest aftermarket parts selections in the game. With all of your preventative maintenance out of the way, we can build up your car to your heart’s desire.

In the car world, we refer to the building process by a simple phrase: “Fast, Cheap, Reliable, pick two”. If you want your WRX to be built fast and reliable, expect to pay big money. However, if you rush the process and go the “fast and cheap” route, you’re probably going to end up with more repairs bills. Going with quality parts crafted by reputable companies is always the way to go.

Coilover Suspension 

Coilover suspension options for a Subaru WRX are endless. From varying degrees of ride height and comfort adjustments, a quality set of coilovers will set off your car. Since coilovers offer the ability to adjust many factors of your suspension in order to improve handling, it is easily one of the best Subaru WRX upgrades available.

If I were building a 4th generation Subaru WRX, I’d install a set of Tein Flex Z Coilovers. The Tein Flex Z coilovers are a great product that isn’t too harsh on the budget but is built by a reputable company. The Flex Z offers awesome ride adjustability and is perfect for a daily driver or occasional track day. However, if I was looking for the ultimate handling upgrade, I’d purchase the KW V3 INOX Coilovers. Not only are you getting the power to adjust rebound and compression independently, but you get the awesome backing of a high end suspension company.

Regardless of your choice, a high quality set of coilovers will prove to be one of the best Subaru WRX upgrades you install.

Aftermarket Exhaust Systems 

Let’s face it, part of the reason you got a Subaru WRX is for that iconic boxer rumble. For decades, that engine sound has been synonymous with rally racing domination and vape-ingesting car enthusiasts worldwide. It is an awesome sound and personally, I think it deserves to be heard. Best part about this Subaru WRX upgrade? Turbochargers love aftermarket exhausts.

After seeing a bunch of different exhaust setups, I gotta say I am a BIG fan of the GReddy Catback exhaust for the 2015-2012 WRX. GReddy always has great sounding exhausts with little to no drone in the cabin. Combined with the quad tip exhaust and the 3″ piping, this setup is perfect for your build.

Lastly, aftermarket exhausts are a nice Subaru WRX upgrade because you won’t need to worry about a tune after installing it.

Wheels and Tires 

With a legendary all-wheel drive system, you’re going to want to have a car that dominates the road. Having the right set of wheels and tires can be a huge performance and aesthetic upgrade to your Subaru WRX.

Personally, I would go with a nice 18″x9.5″ wheel set up with a 245/40/18 tire. This will give you a wider contact patch, nicer wheels, and good specs to avoid rubbing. For example, when I had a Focus ST, I fell in love with the Enkei NT03 wheels I installed on them. I love them so much, that I saw a 4th generation WRX with them and thought they were perfect. Fortunately, Martini Works carries the Enkei NT03 in 18″x9.5″ with a +40mm offset. It is an awesome lightweight wheel that will sit just right to avoid rubbing on your fender, even after lowering it. Since I would want some sticky tires, I would wrap them in Continental ExtremeContact Sport 02 tires. This combination will both look and performance amazingly on a Subaru WRX.

If you want to go more aggressive with larger wheel and tire setups, hit up MartiniWorks. Their experience with different setups will be essential to your build’s success.

Intakes and Intercoolers 

With any turbocharged car, increasing airflow and keeping temps cool is essential. That is where aftermarket cold air intakes and intercoolers come in.

Cold air intakes increase airflow by removing factory air intake systems that have baffles and extra space used for sound dampening. Along with increasing airflow, the cold air intake can be routed further away from the engine, preventing hot air from entering your intake system. Most importantly, the cold air intake will make your car sound awesome. The intake noise on a turbocharged car is insane!

While a cold air intake by itself won’t be a huge power adder, it is a component to maximizing your engine’s potential when you tune the car. If you’re looking at buying an aftermarket intake, Injen has an awesome cold air intake that not only increases airflow but has a layer of heat protection as well.¬†

The Subaru WRX comes with a top-mounted intercooler that is fed air through its factory hood scoop. While this may be efficient enough in stock form, we’re trying to turn up the power. Therefore, we need maximum airflow to keep charge air temps down and allowing the boost to be consistent and plentiful. A front mounted intercooler allows for more air to come in and keep the charge air temps as low as possible. Also, the front mount intercooler will be larger than the factory top-mounted intercooler, providing greater cooling capabilities. You will really see the benefit of an aftermarket intercooler in spirited driving on a backroad or during a track day. Cars without upgraded intercoolers end up dealing with heat soak, limiting your power and engine performance.

With both options, you will absolutely need a good tune. The factory computer systems will go haywire when upgrading anything with the intercooler or intake.

Custom Tunes 

Now that you spent your time and money on the best Subaru WRX upgrades, it’s time to maximize their performance with a custom tune. When you look online, you’ll find dozens of options for aftermarket tunes. Most commonly, you will see Cobb tuning options for the WRX with the legendary Cobb Accessport. However, many car owners simply install the pre-installed tunes from Cobb and call it a day. While it may work decently, a custom tune will be much better for you. This will allow for the specific parts installed in your car to be analyzed and fine tuned by a professional. After all of the data-logging and re-tuning is done, your car will be running extremely well and the power will be there right when you want it.

How Can It Go Wrong? 

When modifying any car, there are a multitude of variables that can result in a bad time. We want to spend our life enjoying our car, not looking at it on jack stands. Avoid these common mistakes and you will ensure your ride will be on the road where it belongs.

Poor Installation 

Number one cause of a bad time: bad installs. If you are going to spend all this money on the best Subaru WRX upgrades you can get your hands on, why let them get installed wrong? If an install is a bit more than you can handle, please consult a professional. This will ensure you get the job done right the first time.

Why No Tune? 

Not tuning your engine for the new modifications you installed is also a big no-no. As mentioned before, the FA20 is already a little temperamental. Slapping on some mods and redlining it without taking the time to tune it is a recipe for disaster. Not only are you jeopardizing your engine’s lifespan, but you are also missing out on the true performance capabilities of your car!

Neglected Maintenance

Previously, I talked about the benefits of having a routine maintenance schedule for your WRX. That maintenance doesn’t stop once the modifications are done. If anything, you will want to pay more attention to your vehicle’s maintenance after tuning it. Please, for the sake of your car, keep changing the oil, monitor your fluids, and make sure bolts and hose clamps are tightened down on key components like your intercooler or diverter valve.


The Subaru WRX is an exciting car to own. What makes it even better is the amount of things you can modify on your WRX. Thanks to a healthy aftermarket and tons of resources, the WRX will always be an excellent choice for modifying. As discussed earlier, take care of preventative maintenance prior to modifying your car. After taking care of your car, make it happier with the best Subaru WRX upgrades available. Get that professional tune and throw a sick set of wheels and tires on your car. Most importantly, enjoy your car because that is ultimately what our hobby is about. Next time we see you here at MartiniWorks, we hope to see you share your Subaru WRX upgrades in the build threads!

About MartiniWorks 

MartiniWorks is a collective of car enthusiasts who love the hell out of their cars. The enthusiast is at the forefront of our minds whenever we create content. We want to make sure you are educated about what you are buying and not being left in the dark. By combining our knowledge along with people like you sharing in The Build Threads, we can bolster the knowledge in the car community and create some amazing rides. 

About Me

My Name is Stef and I am the founder of Powershift Auto. Like MartiniWorks, my goal is to help inspire the future car enthusiasts to embrace their creativity with cars. All my life, I have been deeply invested in the automotive world and it has provided me with some of the best friends and memories I could ask for.

Stef Overton

Automotive Blogger (powershiftauto.com), determined to revamp the car community