[V8FunNaturally]

6MT has zero grinding issue. I have a 2013 and did not have a single grinding. Some people do not know how to drive a manual without ruining the synchros (or they bought their cars from someone who did). And the M3 MT synchros are easy to mess and will get messed up with that type of driver. Once the damage is done, it's there, it does not go away by changing the driver. And that is why you get those people who are decent MT shifters but who bought a used car with messed synchro who will blame the gearbox when they should blame the previous incompetent driver. I know because I bought my M3 new and this gearbox does NOT grind.
I testdrove a DCT at the track for hours. It is the option you need if you do not want your foot and shifting hand dexterity to be a factor in your lap times. But if you plan to drive the car for years on public roads, and like the reward that comes with the responsibility of doing your own shifts. 6MT all the way !
And yes, the DCT is a glorified automatic.