The bike did have high comp pistons in, they had a **** design with a crown on and were shielding half the mixture from the spark plug, as such the bike made 6hp more with new standard ones in !!...... Just for the record the flywheel was a standard one too !
As we get more info on the different setups people have been running, it seems to me that the best package is settling down as a standard, well set up engine, with a good rider