I am sorry to be slow to report on the Jolly Moto pipes. I am also sorry to report that our rider could not describe any difference from our stock pipes on our identical specification twin bike. Even switching one to the other on subsequent practice sessions we could not isolate any engine performance differences, neither good nor bad. We have not tested the various stinger inserts to explore engine characteristics across that range choosing to stick with the middle size insert seemingly duplicating the 'spread of power mid-range' that we seek with our conservative state of tune; also perhaps accepting the limitations of our rider feedback loop. We are now close to the end of a long wait for a replacement right stinger pipe which was damaged in a crash.
We did have to compromise on a longer wheelbase even with the full flexibility of having our rear mounts installed locally as JM lacks a jig for our specific frame mount locations. We were also told by Jim Lomis via Fast from the Past that there are subtle differences even among the 4DP frames as well as the 4TW's so plan to mount your own rear hanger tab.