I used to have the same wheels. I had eibach springs and yokohama AD08 275/30 front and 295/30 rear tires. Ad08's are probably the widest / squarest street tire available. I ended up adjusting my suspension to maximize negative camber in order to make them look "right" (tires stuck out past fenders). The fronts ultimately fit without rubbing (I have run 275's on all my wheels since then). The rear rubbed slightly on large dips in the road even after the camber adjustment. You may be able to eliminate rubbing in the rear with a more rounded tire. 295's on the rear with that offset will be tough to fit if you go really low on coilovers but you should be ok on stock suspension and neg camber. The issue is the offset - 10.5 et 27 allows 295's without problems. The other tire size I would consider is 255/35 & 275/35. That size won't rub but the tires will look a little stretched.
'13 SSII M3 Coupe - KW Clubsport 3-way (Eibach Front Spring Conversion), Akrapovic Evolution, ESS Tune, StopTech Trophy, IND Euro Front Bumper and Gloss Black Mirror Covers, TMS Studs/Lugs, BMW Performance Carbon Fiber Spoiler/Interior Trim/Center Console, BMW Edition Grills/Gills, BMWPedals Extended DCT Paddles, Mode Carbon GT4 Splitter, Advan TC3 (18x9.5/10.5), BBS E05 (18x10/11), G-Force Rivals (275/35/18, 295/35/18)
Last edited by slicer; 12-14-2012 at 11:42 AM.