You'll have some fitment issues, well thats what I encountered anyway. With the K&N, not sure about the drift filter, it fits quite easily in comparison. Unless your chasing every single last kw, there is not much of a point trying to find out which one performs best, not much between them anyway. This is on the CES CAI, I think most CAI are similiar. If you ask me how they sound, thats a totally different story. The K&N filter sings and has a slightly higher pitched induction noise, and the apexi just roars and is louder in general (IMO sounds better).