If you do a full setup from front to back meaning better flowing headers be it because of fewer CELLS or No Cells, Delete the 2 rear Cats and put on a non-baffled muffler. It will sound like a completely different machine. at least for me it did. I dont' think just the By pass pipes is enough maybe you could do some before and after Vids i would be interested. Also I don't think 8 hp would be that noticeable not like 20-25 hp. good luck
