K&N High Flow Air Filter

Part #: KN 33-2304
( 18 reviews )


MSRP: $74.69


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Return Policy | Shipping



Brand: KN
Filter Color: Red
Filter Element Type: Wet
Filter Material: Cotton
Filter Reusable: Yes
Mfgr. Warranty: Million Mile
Return Policy:

RallySport Guarantee - 30 Days

Items that are covered under the RallySport Guarantee offer a 30 day no questions asked return policy.

RallySport Guarantee items may be returned within 30 days of the original invoice date and must include all the original parts and contents for a refund.

The RallySport Guarantee does not apply to products that have been modified, damaged, misused or abused. All returns require an RMA (Return Merchandise Authorization) Number, and freight charges are strictly non-refundable. For more information regarding our freight refund policy, please refer to our return policy page found HERE.


Subaru Impreza
WRX STI Hatchback 2008, 2009, 2010, 2011, 2012, 2013, 2014WRX STI Special Edition Hatchback 2010WRX STI Limited Sedan 2011, 2012, 2013, 2014WRX STI Limited Hatchback 2011, 2012, 2013, 2014WRX STI Sedan 2011, 2012, 2013, 2014WRX Sedan 2008, 2009, 2010, 2011, 2012, 2013, 2014WRX Hatchback 2008, 2009, 2010, 2011, 2012, 2013, 2014WRX Premium Sedan 2010, 2011, 2012, 2013, 2014WRX Premium Hatchback 2010, 2011, 2012, 2013, 2014WRX Limited Sedan 2010, 2011, 2012, 2013, 2014WRX Limited Hatchback 2010, 2011, 2012, 2013, 2014Outback Sport 2008, 2009, 20102.5 GT Sedan 2009, 20102.5 GT Hatchback 2009, 20102.5i Sedan 2008, 2009, 2010, 20112.5i Hatchback 2008, 2009, 2010, 20112.5i Premium Sedan 2010, 20112.5i Premium Hatchback 2010, 2011
Subaru Legacy
i 2005GT Limited 2005, 2007, 2008, 2009Limited 2005GT 2005, 2006GT spec.B 2006, 2007, 2008, 20092.5i 2006, 2008, 2009, 2010, 2011, 2012, 20132.5i Limited 2007, 2008, 2009, 2012, 20132.5i Special Edition 2007, 20083.0 R Limited 2008, 20093.0 R 20093.6R 2010, 2011, 2012, 20132.5GT 2010, 2011, 20122.5i Premium 2012, 20133.6R Limited 2012, 20133.6R Premium 2012
Subaru Forester
XT 2009X 2009, 2010, 2011, 2012X Limited 2009, 2010, 2011, 2012X Premium 2009, 2010, 2011, 2012XT Limited 2009, 2010XT Premium 2010, 2011, 2012, 2013X Touring 2011, 2012XT Touring 2011, 2012, 2013
Subaru Outback
i 2005XT 2005, 2006Limited 2005XT Limited 2005, 2007, 2008, 2009R 2005, 2006VDC Limited 2005R L.L. Bean Edition 2005, 2006, 2007, 20082.5i 2006, 2007, 2008, 2009, 2010, 2011R VDC Limited 20062.5i Limited 2006, 2007, 2008, 2009, 20102.5i Basic 20072.5i L.L. Bean Edition 2008Base 20082.5i Limited L.L. Bean Edition 20083.0 R Limited 20092.5i Premium 20103.6R 2010, 2011
Subaru Tribeca
Base 2006, 2007, 2008, 2009Limited 2006, 2007, 2008, 2009, 2010Premium 2010Touring 2010
Subaru WRX
Base 2015Limited 2015Premium 2015
Subaru WRX STI
Base 2015

K&N’s replacement air filters are designed to increase horsepower and acceleration while providing excellent filtration and increased fuel economy.

Making over 1,200 different replacement air filters for virtually every vehicle on the road. These filters are washable and reusable and are custom designed to fit into your existing factory air box. Their drop-in design means adding performance is simple. With most vehicles you simply remove the disposable air filter and replace it with a K&N.

K&N stock replacement air filters for street vehicles are covered by the famous K&N Million-Mile Limited Warranty™ and will be THE LAST AIR FILTER YOUR VEHICLE WILL EVER NEED.
This product has no user uploaded media. You can upload your photo or video of your install by posting a review.

REVIEWS ( 18 )


Verified Purchase
k&n filter
plukasz2514736 1 month ago
GREAT PRODUCT, really easy to install . make sure to buy the proper cleaning kit for it. love it.

Tight fit but effective
szrobinson57644 1 year ago
Installed in 2015 WRX. Fit is very tight, but with some wriggling it fits well. Customer service at RallySport was excellent. Tuned with COBB AccessPort to 1-93 and car runs strong and smooth. MPG is unchanged, but power is much more progressive and linear. I have used K&N filters on motorcycles and they have provided consistently strong performance.

Great filter
luigidpa_421987 1 year ago
I installed on my 13 sti sedan,I feel the difference much aggressive than the stock filter,highly recommend...thank you rallysport.
Verified Purchase
2011 STi Hatchback
jnaut 1 year ago
Good air filter for a great price and uber fast shipping as always. Thanks RSD!

k&n filter for 2015 sti
DC2UNED 1 year ago
Got this installed tonight, easy to install, since there isn't a wide variety of short ram and cold air intake for the 2015 sti at the moment, this had to do, a little performance gain but better then the stock air filter, you can hear the intake a bit louder now, good product and its washable, worth the money for the time being.


  • AnswerQ: 2015 WRX: Just purchased Invidia N1...  WRX 2015 2 months ago

    Just purchased Invidia N1 from you guys. Do you see any benifits from this filter as my air flow from my cat back is 3 inches now? I'm also nervous due to the high amount of negative feedback on using any high performance drop in filters due to access dirt going to your motor as well as the oil issue. Thanks

    • A: You will see a slight increase in power and response. The issue pertaining to dirt and oil entering the engine is largely overblown in my experience.

      Josh P. 2 months ago

  • AnswerQ: 2014 WRX  draymond 8 months ago

    Meaning is it required to have a tune? I see most people equip this without a tune, still under warranty.

    • A: A tune is generally not required for a drop in air filter, but technically speaking it would be beneficial.

      Nick S. 8 months ago

  • AnswerQ: MAF  mharding94 2 years ago

    Will the oil in this filter mess up the MAF?

    • A: It should not, but it is recommended to clean the MAF periodically to avoid issues.

      Nick S. 2 years ago

  • AnswerQ: tune or no tune?  Steelman87 3 years ago

    I keep getting two different answers to my question. The guys at the local auto store don't know if I need a tune, and the few i'm learning mechanics that i'm learning from say yes for a tune, and some no. I have a 2012 Subaru wrx sedan

    • A: After doing in house testing, you will want to tune the car to run any drop in filter into the airbox due to increased airflow.

      Kirill C. 3 years ago

  • AnswerQ: Tune needed?  jferrett 4 years ago

    Do you need a tune with an accessport when using the high flow drop in filters?

    • A: For all Subaru's (especially 2008+) it is recommended that you tune for any high performance intake filter. That being said you can run this on your stock tune and have little to no issues.

      guest561671092a8d25a1658c55d3 4 years ago