Hello. I have an 05 WR450, which I've done all of the free mods, plus some: JD Jetting throttle stop open air box disconnect grey wire AIS removal I've left my exhaust alone though - I didn't want to spend the money on a new exhaust, and I don't want to exceed the 96db limit. So, is a quiet insert, like the Promotobillet, worth the money? Will I notice a difference in power... Enough to warrant the cash, or am I better off just leaving it alone? If the silent insert doesn't do much for performance gains, is an aftermarket exhaust that meets the 96db limit going to impress me? Thanks! M.