I have found that the 2039 does indeed help the top end a bit. I have settled to running it at large tracks and using the 2035 at smaller and mid sized tracks.

The 2060 is a pipe that seems to work well on many engines, it would be worth trying for people who own them. I don't personally have one, I like to keep things simple and find a couple things I know I can change and stick to it, eliminating variables at the track can streamline your focus and track time. I carry the 2035 and 2039 and have found these suitable for any track I've gone to.