I have them on my E92 M3 when I bought them in London a few months back. 2000 miles and the thread is nearly half gone. Really hard to use them in the damp not to say wet, as it is so damn slippery.
In the dry - now thats a different story. I personally find that the Cups have so much grip (probably at least 20% more). Finally swap them out (including the wheels) and save the Cups for track days.
Exactly the same scenario for me, London in the wet = Bad
in the dry awsome! 20% better grip than standard PS2s, but they dont last long!