hmmmmm.
i switched to race gas and was obsessed with modding the head. unfortunately, i talk english english, but the machine shop guy spoke american english. i had 1.8-2.0mm squish (dont think the bore is fully square) (set by eric on my porting job), i asked for 0.5mm to be milled off, but the bloke took off 0.8mm. i went to a bigger main to stop pinging but it was a tad spoogy (C12+10%MTBE, btw) but the bike would just not rev out as it would before (it revved out quite well, despite the low to mid porting).
so in the end, i had to order a thicker base gasket 0.8mm vs 0.5mm stock, but i am yet to try the bike, so ive kinda reversed the porting (eg base milling) but i am happy to get a bit of top back anyway!
moral of the story. be sure you want it, since it can open a whole can of worms!
cheers
BC