Hi Out There! First time poster from Australia in need of some expert advice. I've got a 2012 YZ450f and I'm looking for either an aftermarket slip-on muffler or end-cap that's noticeably quieter than stock, without killing off the power too much. None of the manufacturers I've contacted can give me any real info an what their products do where noise is concerned and I really don't want to shell out hundreds of $$$ on a maybe. What have any of you out there tried, what's worked and what hasn't?