I bought 5 for the WRX $5 each. 3800 Series tell him K&N do suck, I never would have believed it before reading info here. And from witnessing how much fine dirt was getting by my 502 Ram jet K&N, and now today I pulled the K&N from the WRX and at first it looked ok but I decided to take a slightly damp paper towel and wipe the inside of the intake pipe and sure enough super fine dust was getting by that K&N, even though the clean side of the filter looked good I think dirt was passing. I have not given up on the spectre yet as they are suppose to be synthetic multi layer fiber. As I pull those three I will be looking for signs like I found on the K&N. The aFe look pretty good, thought I was getting the amsoil ones but ordered aFe by mistake for the 350Z but want to know more about them before I put them on it. So anything anyone knows would be helpful. It takes two and they came to $110 for the pair so I will return them if I cannot find more info