I would like to upgrade the exhaust on my 05 WR450. I have drilled out the rivets on my stock system and removed the small restrictor pipe, but it still seems very restricted. I can get a sweet deal on the FMF Q (the original Q). Is this a waste of $, or will I see some performance gain? Should I wait for some type of new unrestricted end cap for the stock muffler? I need some advice. Thanks.