Hi ! For the same reasons, I'm also running (for street use) 18in M3 wheels on my 1M.
I got those 2nd-hand, so the PS2's on them are now 4 years old and must be replaced. Basing my choice on the tyre test in Evo magazine, I'll choose between Goodyear Eagle's and Hankook Ventus S1, who got best results together with Continental's CS3.
See this link for the pics:
http://forum.motorsport-passion.com/...-sa-grem-line/