I bought my Dakar E36 M3 without ever driving a BMW, or even knowing how to drive a manual. Had to have my dad cosign the loan and drive the car home
. Once I knew what I was doing I took the car for a spin, and knew I made a great decision.
Bought my E46 M3 (6MT) a few years later without ever driving that particular model either - simply had it on my dream car list ever since it came out. Worked out great as well.
I've actually driven both DCT and 6MT E92 M3s before ordering this time, but even if I didn't, I wouldn't be worried one bit.
The car is awesome. The transmission decision is a lot harder, though. I had a difficult time deciding, even with extensive test drives. Good luck!