I do... KU31s (195/50/15) on the street..
and v700s (225/
45/15s) on the track. They're my first r-spec tyre and I've been very happy with them, although obviously, I don't have experience with any other r-spec tyre. Best to ask Hellmun. He's basically The God of All Things Black And Round..
I like the tyres, they're progressive, and weren't the surprise on the limit I was told r-specs can be be. Most times I've drĂven the car, it was in some non-optimal setup and I still didn't have any issues with its 'progressivity'. Thankfully, I haven't flat-spotted them yet. It's only in the last two / three sessions that I've been pushing them though..
On the track, they warm up very quickly (1/2 lap?) and are good for quite long sprints, say 20 laps without going off. I haven't gone longer than 20 laps without having to stop to take a leak, so can't say how they will be for longer.
I estimate a set will last about 8 trackdays, and it will be down to the wire by then. You'll have to rotate them to get the most life out of them.
Mine have about 1 or max 2 days in them.. That means about $4/- a lap for the tyres... Wise heads told me not to calculate that, but now that I have, I'm seriously reconsidering the costs of the casual thrills I get from my occasional dabbling in m/sport...
One more thing... Kumho don't make the 225/45/15s anymore... apparently there was wasn't enough demand for the size, so now they only provide 225/50/15s... For me, that will mean, I will have to raise the car, as it will surely rub under heavy brakes > alignment > silly gap on streeties, so it's getting a bit much... OTOH, better gearing..
If you _can_ get 225/45/15s please let me know. I need at least 1, perhaps 2 and possibly 4 ..
well, 1 to replace the front-left which is BALD.
Chris, where are you getting the v700s from that are a better price than the R888?? I'm kinda keen (paragraph 5 notwithstanding)..