Does anyone have any recommendations (or, rather, experience of) replacing tyres?

I read on the US forum that some people are having to change rear tyres every 10,000 miles or so. I've done 12000 KM (just to confuse the distances) and was looking at my rears wondering if they were rubbing down. The tread at the top/side edge of the tyres seems a little worn, although there is plenty of tread on the main face of the tyre that contacts with the road.

I haven't done any track days yet, just commuting. (sad case, I know).

Plus, is anyone getting 2nd gear grinding/clunking in the '04 model (did I ask this before, can't remember....)

kevin