I am in the middle of testing a "gutted" stock setup to the K&N CAI. Last night the car fell off 2mph with the K&N, but it may not be the CAIs fault. The PCM learns (supposedly) what mods you install to correct the A/F ratio, though slowly. I think it went really rich on it.The ET was only off by .006, but the MPH was flat. If it doesnt get better, Ill be reinstalling the stock gutted equiptment and a K&N panel filter. Ill keep you posted.
