New to Thumper. I have an 08 XR650L. So far all I have done is remove the smog pump, put in a Dynojet kit, and mount a GPS. The bike had 7 miles on it when I bought it last year. First owner literally drove it home, and never rode it again.
Carberation much better afetr the jet kit, although still not perfect.
I plan to stay with the stock muffler. Heavy and maybe restrictive, but quiet. I have a great hare scrambles loop that so far I have been able to get away with riding on. It would all be over as soon as I put on a blooey pipe.
My future plans are for a larger gas tank, and probably a self built rear rack hard bag mount combination. I made a bag mount set-up for my Cagiva Gran Canyon that uses Pelican cases that I am very happy with.