i dont think it would make your truck "slower" i think you would get a better sound and probably more low end power. could be wrong but letting more air in and letting more air out frees up more power, within reason.
Oh and if you're looking for more power, try getting a programmer or something. Im sure somebody here can give more info than me.
Last edited by 04BlackFX4; 09-21-2007 at 02:37 PM.