Thought you might want to check out this new wheel from MHT/Niche. They offer M3 specific offsets and seem to be one of the deepest concave setups out there. I am still waiting on information on whether the 19" setup is also offered with the concave but for now...ENJOY!
Load Rating: 1600 (8.5,10) and 1700 (10.5)
Cast Type: Low Pressure Cast