Review on PHILTOP Engine Air Filter, CA9997 GP997 MT-997 Replacement for Impreza, Legacy, Forester, Outback, WRX, WRX STI, Tribeca, Crosstrek, XV Crosstrek, B9 Tribeca - Pack of 1 by Carl Watkins

First off this is a very well made filter. High quality materials and much better than some other manufacturers. These filters are a little thicker than most. This is great for filtering, but makes installation a bit more difficult. Case in point: I installed this on a 2011 Impreza. I had to remove the airbox and install the filter from the car because it was too thick to fit in the car with one half of the airbox still on. But once the airbox was locked and reconnected, there was no problem. You can still open the airbox to check for wear, but to replace it I have to repeat the airbox removal process. To me, it's worth the extra five minutes of work. This may not be the case for you.