Nice write up!
Ill add a few of my own comments.
Just drove my new to me 2010 GT-R back from Virginia and I can say the seats in the M3 are more comfortable for long drives. Was looking to adjust the bolsters when I realized there recaros and don't have adjustments.
The positioning of the the tach in the M3 is in a bad spot if you like the steering wheel down low, whereas the GT-Rs is perfectly positioned. You either have to peak over the top of the steering wheel or scrunch down underneath it to see the M3 hit redline.
The speakers mounted under the front seats in the M3 make the Logic 7 sound system superior to the GT-Rs. The bose speakers in the back seat of the GT-R vibrate the rear window to a blurr.
I agree there isn't the instant throttle response in the GT-R, but when the turbos spool up, what a freakin rush. I haven't heard a peep out my passengers when the GT-R gets going, their speechless, only able to speak after I slow down
And lastly, the GT-R gets a whole lot more attention, most people didn't even know what it was!