Those who runs after performance improvement will usually also be the one who rides hard at high rpm most of the time. In this case the re-programming of the ECU is important for two purposes: 1. Taking advantage of the change in exhaust for performance improvement. 2. Increasing engine life. Just remember: Engine life is a relativeiy, because whoever rides hard at high rpm his engine will not last long.
These are the dimensions I take from NEW MUFFLER GASKET 18392-KYJ-901
("where it slips on to the rest of the exhaust "):
I.D. 38mm
O.D. 44mm

Will this exhaust fit on my bike?
Hey fellas! I’m new here, got a cbr250r about half a year ago. I found an exhaust that I may get for a good price. It was on a scrapped Kawasaki Z750 and seems to be a LeoVince SBK. Would this by any chance fit on a cbr250r from 2011? Pictures attached. Sorry about the angle, it was hard to...
I would try to order an pipe adapter and Muffler hose set from AliExpress, from 100USD you will get a money return.
I find it interesting. It is not clear the quality of the materials in terms of rust etc.
But the good price is for sure.