i have spoken to many people and they all say 305s are usless and slow just today i had 130mph out of mine with simple and reasonably inexpensive modifications all i have is:- custom stainless steel exhausts with art slip on can er5 carbs that have been jetted down a tad i have had the head skimmed and ported and polished a chain and sprocket conversion gpz750R forks and yokes and wheels and swing arm. and boy does it work on a recent trackday i was seeing off my mates hornet on the corners and on accelleration people who bad mouth gpz305s should ride one even standard and it will shut thm up for shure