R888 are semi-slicks. Not good if you often drive in the rain or want to get a lot of miles out of your tires.
But if you don't mind getting only 5k miles off your tires, than the toyo's may be an option. I've had a set of PS, PS2's and now R888s.
When the R888's are cold they're about as good as PS2's once they're heated up they're much sticker. My new concern is that I may break something in my drivetrain when I launch hard--I never worried about that with ps2s.
Another downside of a track-tire, besides limited lifetime, is that they are less predictable at the limits. The R888's give you a bit of warning before they let go, but it's not much. Personally I'd feel safer tracking with PS2's, even if they are a bit slower.
I've driven in wet weather with my R888's and they weren't bad at all, but there's not much tread so I wouldn't want to be caught in heavy rain with them.
As for kicking up rock debris, that will happen more with softer compounds. The R888 will be worse than the PS2's, but it's not as if the PS2's won't be guilty of this as well.
Personally I'm going to stick to R888's on my Viper, I only put on about 1200 miles a year so I doubt I'll be replacing them any more often than the Pilot Sports which seem to last me about 5 years before they're so hard that my car performs like a prius.
