I think what brand you use makes a huge difference, like Steve C I use Pirelli skicks most of the time and they are a very good all round tyre and i get quite a few track days out of a pair, they are even qiute good on the road.

I used Dunlop slicks for while but found these felt like they went off pretty fast, but saything that the GPR70 that myself and Andy use so much often turn blue but soon scrub in again after a little ride.

On my 300 im running Mich slicks (cut a tad) on the road and track and these seem to be lasting forever, although they arnt that sure footed on the salted roads we have right now, makes for fun riding though!
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If I have to take the carbs off once more...