Well, regarding the stock POS pipe:as soon as we had the 1st a55 out of the box and ran it, and found out it only went 27, we did what any motorhead would have done. We cut open the pipe and looked inside, and found that steel wool crap in there. My first thought was that somebody left their chrome cleaning supply inside.We ditched that, and cut the "windowpane" to make a bigger hole, then welded it back up and painted it. All that effort produced a 1 mph gain.
We discovered the sprocket change and that brought it up to 34-36. That Streetmate went to a guy close to the shop. He was back every Saturday for 8 or 9 weeks, to try to fix the idle problem.
A couple weeks ago his 6 months warranty was up.Except when they shipped the 1st few bikes they didn't put any manuals in the boxes, so he didn't get his warranty card until about Jan or Feb.!
So when he came in the last time , it was with less than 2000 miles on it and where we welded the pipe back together: all the paint was burnt off and the weld rusty
Tomos came out with the speed kit which is the pipe and jet.
They also have an upgrade kit which is a higher ratio head, a different air intake and a jet, which I think is the same as the speed kit jet.That one's a freebie from tomos, since it's part of a recall type situation.