AEM 21-478WR Subaru Impreza WRX Cold Air Intake

A Cold Air Intake for Subaru WRX and STI

First and foremost, be sure this intake fits your exact model Impreza. You can easily find out by following the Amazon Compatibility Chart (click on “See all vehicles this product fits”).

The AEM 21-478WR Air Intake System
When it comes to air intake systems engineered to produce massive horsepower and torque gains, there is no one better than AEM. With an average increase of 36 horsepower, this application was designed to be a game changer.

This aftermarket intake system has been tuned and dyno-tested to specifically fit the 08 – 14 Subaru Impreza WRX and STI equipped with the 2.5-liter boxer engine.

With the easy-to-follow instructions including all the hardware required for installation, it won’t be long until you’re out making a name for yourself in the streets.

Why the AEM 21-478WR is the Best Cold Air Intake for the Subaru Impreza WRX?

By ripping out that old restrictive intake system and replacing it with this inexpensive aftermarket bolt-on kit, you really open up the flood gate in terms of performance.

This Subaru Impreza WRX cold air intake will give you some of the best performance gains we have ever seen from an easy to install bolt-on application.

The reason is by default the stock intake system is nested in the engine bay sucking in extremely hot air. Anyone who has owned one of these vehicles know that the engine get extremely hot in a very short time.

What AEM did was placed a heat shield to block that hot air from being sucked into the engine. The mandrel-bent aluminum intake tubes work their way down inside the fender where an over-sized reusable synthetic air filter sucks outstanding amounts of cold air.

That high-flow of cooler air feeds your 2.5-liter flat four boxer engine with more oxygen acting like gas to a fire. This results in more combustion, allowing your engine to produce more power by relieving stress off the motor.

Your name will be all over your neighborhood after you purchase this Subaru Impreza WRX cold air intake.

What Do We Think?

When reviewing this AEM cold air intake in our 2008 Subaru Impreza WRX we definitely felt like Joseph Cross’s character, Danny Krueger, in the movie “Born 2 Race”.  It was like we had a chip on our shoulder to prove that four-cylinder cars can keep up with those big V-8’s.

Once we got on the road, we put our foot to the floor board while banging through the gears. The performance gains you will feel with the AEM 21-478WR Subaru Impreza WRX cold air intake are ridiculous for this inexpensive aftermarket bolt-on application.


A Cold Air Intake for Subaru WRX and STI

The sound of the engine is like a demon that has awoken from his slumber and decided to unleash its wrath.

With a deep growling tone, the motor just sounds pure evil. The BOV lets out a louder, more aggressive sound letting people know you mean business when cruising the stripe.

After stirring up the neighborhood streets for an awhile we did notice that we got a little increase in miles per gallons.

Although it was not dramatic, it was a very nice addition to everything else with this system has to offer. We cannot recommend the Subaru Impreza WRX cold air intake enough.

Whether you are a car enthusiast or not, this application will make anyone happy when they purchase it.

What We Like About the AEM 21-478WR Subaru Impreza WRX Cold Air Intake:

  • The power gains of this product are like none other at a whooping 36 HP claim.
  • The engine sounds like a demon from hell.
  • The high-flow air filter can be washed and reused.
  • You may see an increase in your miles per gallons.

What We Did Not Like.

  • This is not really design for the casual driver.
  • The dyno-test was based off the STI so the power gains in the WRX may be less.
  • The increase in miles per gallon were minimal at best.

Buy It or Pass On It?

By now you probably already know where we stand. This is a must buy for anyone who loves to drive. When you buy it, you will quickly understand why we say that.

The engine noise is a lot louder than stock making long drives a bit annoying if you are trying to listen to music when you get on the throttle.

Unlike many intake systems, the Subaru Impreza WRX cold air intake system does not increase your fuel economy that much.

This did not bother us that much because the power gains that this intake system produces is more than enough to sell itself. If you do not pick this cold air intake system up you will definitely be robbing yourself from a lot of fun.

Key Features of the AEM 21-478WR Cold Air Intake:

  • Estimated horsepower gain of 36 HP at 5300 RPM
  • All AEM Air Intakes come with a lifetime DRYFLOW Synthetic air filter with great filtration
  • Guaranteed for the life of your car or truck
  • Manufactured in the USA

AEM 21-478WR WRX Cold Air Intake installed

What Other People Around the Car World Have to Say Direct from Amazon:

“The power gains from installing this AEM CAI are incredible (especially when paired with the Cobb AccessPORT) and the sound that this intake provides is awesome! You can really hear the air being sucking into the engine and a BOV’esque sound when you shift after about 3500 rpm’s.

The install was relatively easy, it took a little bit of muscle to work the pieces together but all-in-all it took about 35-45 minute to remove the factory air box an install the new CAI. I would HIGHLY recommend this product to anyone considering buying a CAI for their car. – Iggy

“I purchased the Cobb access-port before I purchased this and was pretty satisfied. Then I bought this and reflashed my ECU with the Stage 1 93 AEM map. Big difference in both performance and sound.

You can hear the massive air induction when you stomp the gas and when you shift the once quiet recirc valve is much more prevalent.

The install was pretty easy. I forgot to install the rubber surround on the air box where the pipe passes through so don’t forget to do that. I’ll do it when I clean the filter. Good buy. Amazon had the best price of anywhere I checked on the internet.” – Terry

Where Can I Buy the AEM 21-478WR Subaru Impreza WRX Cold Air Intake?

Amazon is the best place on the internet to buy this product. All sells are backed by their incredible customer service. You will have this product in no time with Amazons fast shipping service.

One thing someone may not be aware of is that Amazon allows other sellers, offering the product both new and used, allowing you to get a much better price than most other retailers on the internet.

Check out the price and you may been shocked when you see someone selling this product cheaper than retail!

Buy it from Amazon



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