[Twitch Massacre]

Somehow I find this question a bit pointless in my opinion. My wife drives a 640i GC and as fine a car as it is, it does not hold a candle to the M6 or any M for that matter. Forget the extra HP, that's besides the point. The driving dynamics in the Ms are what it is all about, if you can't appreciate that then the M6 is just not for you (my wife included). The CF roof holds a practical purpose, it's not just there to look at (and I have to say on the F13 it's the best looking roof I've seen on a GT). The adaptive suspension, steering, throttle response have all been meticulously designed and optimized for each style of driving. And the M-DCT is the perfect pair for the S63TU. How can anyone prefer an 8 speed (torque converter) automatic to an automated dual clutch for sports driving? Enough of the aggressiveness was lost in phasing out the SMG III anyways, and yet with the smoothness of the M-DCT the M6 is finally every bit as good for daily driving as the non-M cars. For as much "spice" as M cars have lost over the years they are still the finest cars BMW produces. Every time I get a loaner it spends it's time garaged. There is just no going back. OP, if you simply want to get from point A to point B in a fine German automobile then get the 650i, you'll love it, but if you're looking to DRIVE, to really be immersed in an experience and be in control, then you know where to look. I'm sure by now you know exactly what you're looking for in a car and why.