With the SMG you can do "Launch Control".
Ask if the car has had any vanos problems.
With SMG you have the feeling you're driving manual in terms of momentum forces with shifting. Example: Going from 1st to 2nd in a hard pull, you can feel the car disengage the clutch and reengage, pushing you back into your seat.
When you're on an incline the car will roll back like a manual,due to the clutch being open, until you apply more throttle. With an auto the car does not have this behavior.
Reference: '07 M6 SMGII
"Power is nothing without Control" - Pirelli.