My friend has a 335xi that he ran 12.2 119mph with a helix intercooler, downpipes, Cobb, and 100 octane. 55 degree night at Atco raceway nj. I would have to think with the weight of the 135 with these mods should be .3 faster. It would have to be with drag radials though. They're key.
Afe Scoops and CAI, PBX, 261M's Powder Coated Gunmetal, 225/255 Michelin PSS, (BMW Performance: BBK, Illuminated Door Sills, Shifter Knob and Boot, E-Brake Handle, Steering Wheel, Front Strut Bar), E93 FSB, E92 RSB, M3 Rear Subframe Bushings, M3 Front Control Arms, HPA coilover kit (Koni Adjustables and Swift Springs), Steel Brake Hoses, Black Kidneys, Smoked LED side markers, LED angel eyes, Blacklines, Carbon fiber spoiler, Ambergones...