I've had a 2012 gtr and traded it in for my 2013 M5. The gtr was a great car , and I enjoyed it . But it never felt like a 100k car and I was always worried about resale value once out of warranty. When the gtr was driven as it was designed it was lots of fun. But as a daily driver or multi use car not so fun. The suspension is very stiff and not much room in the back seat ,if you have kids. Next problem or not depending on your demeanor . Every one you pull next to wants to either race or has the urge to ask you how much you paid for that, very annoying.
The M5 is hardly recognized by people around you. Unless they are car people then you'll get the thumbs up. This car can be driven just as hard as the gtr or just as you would with a 5 series. Other thing that concern me about the gtr was Nissan looking for any reason to void the warranty . (black box recorder in the car to inform them when and where your car broke) supposably not covered if at a track
Although I miss my gtr now and then, that feeling goes away once I set the M5 in sport plus mode I'm good to go !
Ps I've tracked both cars at the drag strip 11.0 for the gtr and 11.7 for m5 both cars were completely stock. Not such a big trade off since you get two cars with the BMW! Race car and cruiser with the touch of a little button called M !