I completely agree with your assessment about the lack of torque...but don't worry it's fixable!
I absolutely loved the precision of the M3's handling and the DCT was phenomenal but the lack of torque coming from a 19psi/meth 335 was a problem for me.
I did get a chance to drive in a 400 RWHP 6MT M3 with only a catless mid-pipe and tune, and OMG it made a HUGE difference. The mid-pipe gives the M3 a good 20-25 lb ft of torque throughout the entire RPM which is particularly needed in the mid-range.
You may not have this opportunity to try one first that's modded...but ask around in your Regional Forum if there's someone who's modded who could take you out for a spin.
Daily: 2013 e92 M3 MW FR DCT ZCP / ESS VT2 650 S/C, MRF mid/Akra slip, ST BBK
Track/Airstrip: 2011 997.2 Turbo S PDK / GIAC tuned / Ohlins coils+LCAs+endlinks setup by BBI Autosport
Beater: 2013 X5 3.5sport