Thanks for the comments. :)
Herr Tod, I'm going to have to think about what tyres to get next time. I use the bike for commuting and weekend rides, so I don't want anything too soft. At the moment I'm thinking I'll go back to sport demons since they seemed to let me scrap pegs, which I haven't done on the GT501's. Plus they're cheap since they're cross-ply's. But then maybe I should try some more expensive radials... I don't know.
andrewsw, I was getting up to an indicated 180km/h towards the end of the back straight.