I dont really know how much my mileage was affected, but i have an AIRAID intake and just a flowmaster 50 series delta flow. the intake makes the turbo sound like a jet and the muffler adds some balls to the sound but its still quiet enough in the cab when the windows are rolled up.
I have the afe intake and bd 4 inch exhaust and don't have any complaints. but un like him mine is loud but im used 2 it course i have the 2nd gen they r not nearly as quiet as the newer ones
I had a K&N intake on my '02 with 4" strait pipe. There was not better sound far as I am concerned. Like the others said, the turbo whistle was like a turbine winding up. I passed a buddy in a log truck one day when we were chatting on the CB and he made comment on how healthy it sounded. I miss that noise some kind of bad but I also love the power and room my '06 has.
