I just bought an '05 WR450 with 280 miles on it (still has the original tire). I am coming from a '86 TT600 and let me just say when I got on the 450, I could NOT believe the speed and power! The only mods that have been done to it that I know of is the gray wire has been cut, and the throttle stop taken out. The exhaust has been replaced with a White Brothers E2. I am getting back into riding after many years (my son is 10 and has an XR80), so I know I can't expect to ride like I used to. I grew up climbing hills. It is what I love the most, so I am looking forward to finding some great places to ride in Alabama. Now for the questions: What other mods should I do before I take it to the trails in a couple of weeks? The E2 doesn't have the spark arrestor and is very loud. How can I make it quiet? I put the factory tailpipe back on for now. I noticed the link to ThumperFaq but that is for the WR250. Do the same mods apply to the WR450? Finally (and most importantly), I am 5'8", so the bike is a little tall for me. Where can I find detailed instructions on lowering it a little bit? Thanks. Hope everyone is patient with the newbie questions that will come your way.