I have one on my 01 attatched to an aFe stage 1 and HBT2 62/12. No difference in sound, it's just a "cleaner" look over the accordian rubber stocker. If you want more noticeable turbo drill a 4" hole in the cowl.
BTW, I use the "dial-up" thread and can't see what year your truck is, so if you're 3rd gen. , disregard the hole in cowl stuff.