Praise first: I LOVE IT. I am seriously jealous about your manual skills and mechanical expertise. Chapeau!

Now the criticism (hope constructive): I don't like the exhaust. It reminds me exactly of the taxi bikes, and you want to avoid that. The best, in my taste, would be something that runs parallel to the back part of the seat, this way you would have harmonic lines. However you have never posted a pic taken from the right side of the bike no angles, so it's hard to judge.

Again, WELL DONE and keep up the good work!!!