is it recommended to replace the stock air filter with an aftermarket one?? if so which one is generally reommended?? K&N??

 

I use a JR which has been the subject of various group buys. Dunno if it's still true but the K&N did not have an S2K-specific part for the S. That may have rectified by now.

Dyno tests show a 2-3 hp gain over the stock paper filter...