This happens to be my area of expertiece! I have a gytr slip on with a gutted cat. In general these are already loud slip ons, but I have shortened mine just under that gytr sticker. That gave it a nice jump in volume. But if you really want to get it screaming, do like the previous guy said and get a gp shorty pipe from ebay. Make sure it has a 2 inch diameter and you'll be set. That bike will screem if you do that. I have also found that by taking out the paking in my gytr it is about the same as the gp shorty pipe. The problem with those two things is that you lose all your backpressure and therefore lose power. It will be loud as hell, but that nice kick in the pance power will be gone. If I was you, I'd do the same thing I did and just find the pipe you like and shorten it. This keeps the power and bumps the volume. And with some pipes like mine (gytr) you can remove the packing whenever you feel like wakin up the neighbors and put it back in when you want your power back. Hope that helps
