your first point, sorry i may find this difficult to explain but, i dont think this will matter. the horsepower of the dct and manual m3's are exactly the same. the ways round the gearbox situation are, if you wanted to drive it as a pure manual and lose a little time accelerating you can use a g25 wheel with clutch. if you want to drive it as an automatic you can use a pad or any wheel. and if you want to use it as a sequential like me with no lift off there's the pad and all the wheels out there.
as for launch, yeah who knows? probably not, as to select this would mean doing a setting in the 3 seconds you get before race start. i think poly will have considered how fast each car can launch in its best setting.