I've never driven a GTR, but I'm not all that convinced by it. Yes, it's superbly cabable, but that's because of some pretty fancy trickery. In everyday life, how many times do you need that acceleration/deceleration or want to pull 1.4G in a corner?
I'll keep my E class and the Porsche, thanks very much.
The Porsche may not be as quick or as technically advanced as the GTR, but I don't want it to be.