I added more than just a couple of inches when I made my cross over pipe, and still pulled 65 rwhp, the bike runs crisp and clean. thinkin balance tube block off next.
I like your twin pipe single side. reminds me of my old S4R 996 Monster.
Heres a long pipe for ya.
Oh and as for the left mount. thinking i may put a small leather bag for some tools on there.