If you look at the Summit Racing site under exhaust inserts, you will see the ones I am talking about. They come in different sizes. I got the 2.5 inch one and put it in the main pipe just in front of the muffler. My exhaust installer cut the pipe, put the insert in there and tack welded it in place, so it can't move around. He then rewelded my pipe shut and BINGO, no more harsh noises. Muffler sounds great now and no change in performance.

__________________
06 SLY, Sand&Steel, Clear Bra, CAI, TRI-Y long tube headers, high flow CAT, Magnaflow cat back dual exhaust, ECM tune, painted calipers w/decals, large bore throttle body