I've been running a K&N filter in my 03 Mach1 almost since day one, and it has 30K miles on it. I clean the filter each time I change the oil in the motor, and of course oil it. I have yet to see,hear or feel any difference in the performance of my 32 valver. I did, however spray some special cleaner into my MAF and used a Q-Tip to clean it, and I only did that because of a tip from RModel65. It didn't change anything, but I guess if the MAF gets dirty, then just swab it and then you will be good to go.