Ofcourse torque porkers do have their ups and downs.

The fancy sequentials and dual clutches can't stand that amount of torque (well the Ricardo twin in the Veyron could, but it costs more than an M6 if I'm not mistaking).
So that means good bye super fast upshifts (and downshifts in SMG's case).
Also it can't be geared as low as the V10.

So there is a price to pay for the torque.