I just picked up an 06 WR 450 as well a couple of months ago. The first thing I had done to it was removed that throttle stop. You can buy the kit to change it for about 20 bucks. Second, remove the existing single air intake and change it to a dual intake which add more air flow into the engine. Third after your first hundred miles on the bike it's best to have a valve job done so the valves don't tighten up, and the last two items to get your WR screaming fast is add a aftermarket pipe & disconnect the "grey wire". Hope that helps.