Surprising you had such a negative experience with the M340i, I've only heard good things..
As far as the 'low end torque' goes, I'm pretty sure it wasn't heat-soaked, as the 340i has a similar cooling set up as the M2C.
It's just the B5801 in the 340i is tuned to have more mid-range grunt, instead of being mapped front-heavy and blowing its load early by just spinning tires.
It caters to the sort of audience who wants a sporty vehicle but not necessarily a sports cars. The potential power is definitely there and I would love to have one as a daily, if it didn't cost 70k fully quipped...
