I think people are adding NPP mufflers on their '05-'07 without a retrofit kit, thus the mufflers are always open and some drone.

B&B PRT is thier headers or stock system only. If you have Kooks with cats it will not work.

I had B&B Rt. 66 with kooks 1 3/4 and high flow cats and the drone which was just at 1,500 made me switch to Corsa Sports. The Corsa's have zero drone, but they are very loud at WOT. When I had the Corsa and B&B on the floor next to each other the build difference was incredible. B&B is built like brick **** house. Corsa built well, but about 20 lbs lighter.

you can swap out your rear end--

you can change your shift points a bit with a tune- run lower gear out longer

or use your gear shifter more

if you hiway alot get a rear and a tune

that will fix most of it