I second the motion for the Bridgstone S20R. Available in the correct sizes. I've running them on my other bike, and like them enough to buy them again.
Since 2013, I use my 610 only on tracks. I started, the last year, with a front ContiAttack SM and a rear 160 Michelin Power Pure 2CT: this provided a great grip, considering the durability (more than 3k miles on the road with the previous one). I replaced it with a 150 ContiAttack SM, which I used the last Saturday for the first time. I chose the 150 because of my OEM rims. IMO with the Conti: -I can lean at least as much as I could with the the Michelin, or maybe more, -the bike is faster to lean and it's not slower to raise while exiting the corner, -it definitely gives a better feeling while sliding (but maybe the not so good feeling of the Michelin was caused also by its wear; I remember that when it was new it slided better), -it gives a better feeling of control in general. Maybe what I've written is due to suggestion (I really doubt it), but one thing is sure: some weeks ago my laptime record was 2:10; Sunday, with the new tyre, it became 2:07. I don't know whether it was the tyre or my skills improvement (I'm not a complete beginner, but neither a veteran), but three seconds are many and make me think that the Conti can't be less performant!
I was thinking about the pilot road 3 or 4, but I went with a 160 dunlop Q3 for now. It is supposed to be a dual compound. I only have a few hundred street miles on it so far. I did notice a little bit of a gearing change by going with the wider tire. I think the gearing is better now. The Q3 is what was on my 625smc too. I was hard on them with no issues.
