I've had A048s,R888s and Kumho V70a on my mk2 Golf track car, drove all the way to the ring and back and did 30 laps on them (R888s) a few years ago, still 'just' legal on the fronts when I got back, wet track they are good, but shit in standing water on Belgian motorways 'Aquaplanage anyone?'
A048s were great on track but tramlined terribly on road, I had hard front and medium rear Kumhos on the advice of Camskill, they wore very well and were great once warmed up.
Agree with jimbo's comments on R888s on heavier cars, heard a lot of people say they don't work on cars 1300kg+ , however I saw a few M3s running them at the 'ring last weekend.
Another point to running things like R888s on the road is the noise they make, on the run down to Schwedenkruez on the 'ring (130-140mph) they sounded like a Stuka dive bomber.
Yokohama AD08s get good reviews and are not as track focused as the tyres I mention above, sort of an in-between thing.
If running 18s something like Michelin Pilot Cups (as fitted on CSLs/GT3s etc) might be worth thinking about, they are pretty shit in the wet though I'm told. (the link says they're good in the wet so ,feck knows!)
http://www.michelin.co.uk/tyres/mich...ilot-sport-cup