So, I bought and installed a K&N Filter about 2-3 years ago when I did my BFI. Just cleaned and re-oiled it for the FIRST time last night.

WOW. Truly, maintenance is by far the most cost effective thing you can do to make your car faster. I can feel more power throughout the entire powerband, especially up top. It even sounds a little louder. Hopefully my gas mileage shows similar results.

If you have a BFI, the air filter really needs to be relaplaced/cleaned often. Because the filter gets so much "fresh" air from the outside of the car, It really cuts down on the life of the filter. I found tons of crap in it.

Seriously, I know this has been beat like a dead horse, but before you start shelling out for that exhaust, do some basic maintenance. Replace your rotors, wires, plugs, all your fluids, flush your trans and radiator, air filter, fuel filter, seafoam it and whatever else you can think of, you will be surprised how much stronger your car will run.

 

I used K&N filters on different cars but lately I have stayed away from them and wet oil filters in general. Dry filters like the apexi are what I use now.

P.S. The best "mod" is a transmission cooler.

 

I have heard that the oil ends up getting on the maf/map sensors, Some spray cleaner will fix this.

 

WAIT, THIS IS WRONG !

If you have the earlier karmen vortex type maf, DO NOT spray anything inside your MAF because it is not a hot wire sensor. If you use maf cleaner on it, their is a good chance it will ruin the sensor.