The GTR is amazing, but the ZR1 is better in every aspect except for interior treatment and stability control management. I do have to say I like the look of the GTR more, but the ZR1 is pretty much equally as appealing to my eyes.
I'd rather have a 6mt with 600hp+ in a lightweight sports car than a DCT-equipped AWD beast. There's plenty more fun to be had with the ZR1. I've read/watched several reviews saying that the GTR is built for speed, not excitement. AWD is efficient, but it's just not as fun.
Also, in multiple comparisons between the ZR1 and GTR, most editors claim that the ZR1 is the better DD. The magnetically-adjustable suspension seems to cope with real-world roads much better. I heard the GTR is still stiff, no matter the suspension settings.
Past:'08 E92 335i|ZPP|ZSP|6AT|four (4) HPFPs
Present:'15 Mustang GT|401A|PP|6MT|Recaros
Sig pic unrelated. I like to go sideways and stuff.