Thanks Chopper. I realize that HP gains of 5-15 would not really be felt/noticed. Sure it won't hurt but I'm not buying a muffler specifically for HP claims. I'm mainly concerned with finding a muffler a little more tame than what I have, but I don't want to get another muffler that's ALSO too aggressive for me and go through this process again. Yes, I can always get an OEM one but I would be spending big bucks for something that we know is overweight. I've not had much luck thus far with finding hard data with respect to noise levels, like at WOT. Appreciate the input though.