Long Term Review | STILLEN Hi-Flow Intake for 2015-18 Subaru WRX

Long Term Review | STILLEN Hi-Flow Intake for 2015-18 Subaru WRX

The 2015-18 Subaru WRX is one heck of a car, once again delivering on Subaru’s winning recipe for all-wheel-drive fun. As with every Subaru of the last 20 years or so, enthusiasts are feverishly modding 15+ Subaru WRX’s.


STILLEN Front Splitter for WRX / RS-R Coilovers (1.4in Drop) / Wedsport SA72R 18×9.5 / 18×9.5
265/35-18 Nitto NT05 Tires

In their zeal to throw parts at it as quickly as possible, the FA20DIT engine has developed a reputation for being notoriously finicky among Subie lovers. In particular, the issue is that many aftermarket intakes cause a Check Engine Light or worse, resulting in quite a few ‘horror stories’. All the ‘horror stories’ have created the impression the motor will blow up if you look at it wrong. While that’s a wild exaggeration, there is some truth to the fact it’s fairly easy to hurt these motors.


STILLEN Front Splitter for WRX / RS-R Coilovers (1.4in Drop) / Wedsport SA72R 18×9.5 / 18×9.5
265/35-18 Nitto NT05 Tires

Longevity with a performance car like the WRX can be a concern, so that’s why we wanted to take this opportunity to do a Long Term Review of the performance of our Hi-Flow Intake for 2015-2018 Subaru WRX to see how it really held up in the real world.

Subaru WRX 2015 Intake Installed View 1

STILLEN manager Dean has been running the STILLEN Hi-Flow Intake for 2015-2018 Subaru WRX on his daily driver WRX for the past two years – without issue. As you may or may not know, the STILLEN WRX intake doesn’t require a tune to make the power advertised or to avoid a CEL.


Dean’s WRX runs a basic COBB AccessPORT for tuning and datalogging, a KILLER-B Intercooler, as well as the prototype STILLEN Exhaust for 2015-18 Subaru WRX (currently in development), and that’s about it.


STILLEN Exhaust for WRX (PROTOTYPE) / RS-R Coilovers (1.4in Drop) / Wedsport SA72R 18×9.5 / 18×9.5
265/35-18 Nitto NT05 Tires

Dean’s WRX is not ‘wildly modded’ by any means, and it’s worth saying Dean doesn’t drive like your grandma – he also enjoys spirited driving in the Rex. After 2 years of normal commuting and typical maintenance, Dean’s WRX is still running great – no check engine lights, and the motor has not exploded. Furthermore, it still makes every bit of the power it did 2 years ago.

2015-2018 Subaru WRX Hi-Flow Intake Kit 402000

PN# 402000 – Mandrel-Bent Aluminum Tube, Black Powdercoated Finish, Compatible with OE Air Duct

Given the FA20DIT’s ‘reputation’, that’s remarkable. The OEM airbox is rather restrictive and could really be in virtually every regard, airflow, sound – which is part of why our intake was able to safely achieve 30WHP gains.

This really highlights the value of the work we put into developing our performance parts here at STILLEN. When we were designing the STILLEN Hi Flow Intake for 2015-18 Subaru WRX, we wanted to create an intake that delivered power safely and would work well with the OEM ECU.


Dean tells us that around town, the intake sound remains fairly subtle until you tip in the throttle, offering an intoxicating and rich boxer four intake note, yet is still quiet enough to have a conversation with passengers. Given the power gain, longevity and sound level of this intake, this intake is a great option for any commuter WRX or any WRX enthusiast chasing horsepower.

That’s another quality we strive for in our performance parts- we aim to offer subtle, refined tones in our intakes and exhausts that sound GOOD, avoiding obnoxious drone and unnecessary noise that can take away from enjoying a car.

After dozens of prototypes, we settled on a shielded design that retains the factory air duct – the end result being a walloping 30whp / 32wtq peak gain. That’s one of the perks of doing all of our manufacturing in house – since every STILLEN intake is manufactured right here in Costa Mesa, CA, we’re able to produce and test numerous prototypes to fine tune diameter and design for safe, reliable, consistent power.

Stillen 2015 WRX 1v5

We wanted more than just “peak numbers” with this system – by carefully tweaking the airflow, we were able to make a huge dent in that infamous FA20/FA20DIT “torque dip” between 4300-5500 RPM that normally takes the fun out of things, offering a huge improvement in usable power across the entire rev range.


STILLEN Front Splitter for WRX / RS-R Coilovers (1.4in Drop) / Wedsport SA72R 18×9.5 / 18×9.5
265/35-18 Nitto NT05 Tires

Considering that our intake delivers huge power, nearly eliminates the infamous torque dip and won’t cause a CEL, we’re not just blowing hot air when we say the STILLEN 2015-18 Subaru WRX Cold Air Intake is quite possibly the best intake for FA20DIT WRX models. The only question left is – why don’t you have one yet on your ‘rex?

Talk to our Performance Counselors including Dean. Give us a call today at 866-250-5542, shop online at STILLEN.com or chat live with us at STILLEN.com