hey all, my air filter needs to be changed, and the question of best replacement comes to mind again... 3 options: stock one, k&n inlay, custom cai cheapest solution is no doubt to get another paper filter... but it would be nice to gain a bit performance, right ? so, k&n inlay filter is pretty easy to come by and easy to install custom cai, is harder to make but should give better results ? what is the best choice ? my car is completely stock now, i might be changing the muffler one day (don't know if this is relevant ?) also, i read a CAI makes you lose low RPM torque, why's that?