I never understood the M3 Cab either!?
Strictly bling. As for SMG, it's the ONLY way to fly! It's unbelieveably fun to drive. The 'smoothness' issue refers only to when you use the 'auto shifting' mode. It's awful in that mode. Which brings me to the 2nd thing I don't understand about M3's - why is there an automated mode in SMG? Answer: because there can be and it might sell a few to people who probably shouldn't be driving these cars anyway. I NEVER use that mode and don't know anybody who does. I use only sequential manual mode with the paddle shifters and stability control switched off - it's a religious experience.