Just the pipe is different. Probably not wise to drill a hole in a spec exhaust.
But just grab a 3 pipe and throw it on and you should be fine. You can run a bit more RPM with the 3 pipe compared to the 2.
Thanks for the reply, it is extremely hard to find any info on these things by doing a google search. Just doesn’t seem to be that much info out there. So just to be clear:
Pipe: switch from kpv2 to KPV3
Header: keep same
Carb: keep same and no adjustments
Timing: keep the same
Trying to find a used one, eBay doesn’t seem to have any and the classifieds on this forum have crawled to a snails pace since the forum change.