I was all hyped up couple of weeks ago about buying an Akra slip on but now something is holding me back. I dont know, maybe I should just leave it stock. Is it really worth the 400+ bucks to get this slip on? Does it lower or gain gas miles? Just want to hear some of you Akra slip on owners inputs. Now that you have it and messed with it, would you do it again or just forget it and leave the damn bike stock?