RE: Piped Super Tigre .51
I haven't tried it on my China made 51 but I had an older Italian made 51 that I raced on a Scooter II and it gained about 1500 on a pipe. It takes a bit of work to get the header trimmed to the right length though. I think Macs has a chart showing total pipe length measurements on their web site for most engines using their header and pipe combos. That helps getting into the ball park when tuning the length.