I've owned the manual e92 M3 and now own a DCT M3, the DCT is definitely easier to drive fast and it has much shorter gearing than the manual. So you can stay in the power band more of the time (6-8k rpm). 7th at 100km/h is roughly the same as 6th in the manual at 100km/h
Just getting used to the M3 from a turbo car, you need to have a different mentality. Don't weary of revving it out, that's the way it should be driven to get the most enjoyment from it. Revs vs torque, but it will get you to the same place. I personally prefer high revving engines, even though it can be a pain at times in daily driving, I find it more rewarding when you're working harder with the car to drive fast.
Just make your you get a good quality exhaust like an akrapovic evolution...the standard exhaust is far too quiet! Also the power gain form the akra is noticeable! Other easy mods are drop-in filters and underdrive pulleys...top it off with a tune and some people in the states have been getting 400whp, although the figure isn't necessarily important, the gains over the base line dynos are significant (for a highly strung NA car anyway)
2010 Porsche 911 GT3 (Carrera White/Black)
2010 BMW e92 M3 M-DCT (Frozen Grey/Black) - Sold
2007 BMW e92 M3 6MT (Jerez Black/Palladium Silver) - Sold
2002 BMW e46 M3 SMG (Titanium Silver/Black) - Sold