I've been running R compound tires on the street, during the summers, for 20 years without a single puncture or failure. For a performance car driven in canyon type driving, they are simply the best. They are bad in rain and when they do heat up and get soft, sure they pick up gravel, but all that becomes negligible when you feel how they can transform a car's performance. If you search for reviews on the R888, some people are getting over 10k miles on the street. So, if your needs fit this model, and you're not concerned about getting 50k miles out of a tire, then I heartily recommend that you try them.
Granted, they were not bad as far as tread wear (~14K miles or so) and getting flats went, but, they also were not HALF as sticky as the R888s.
The RA1s, even though many (and maybe even Toyo themselves?) claim that they are the same compound as the 888s, do seem to be a little harder compound wise, as well as as somewhat better in the wet due to their tread pattern, and deeper full tread depth.
In any case, YES, IF people are really getting > 4K miles out of them on the street, I WILL consider them, or maybe even the RA1s if I am worried about standing water on the roadways (the 888s DO look much cooler though).
THANKS for the cap info!