I had a 2009 M3 DCT Sedan, I now have a 2012 135i MSport DCT. The 135 is faster in town, where most of my driving occurs. Plus, cost of running an M3 exceeds the 135 by quite a bit.
I would NOT trade back for the M3.
2016 340i xDrive MPerf. EBII
Previous BMWs - 18 others since 1971.