GT-R maint. is a pain in the ass. However for $50K+ the M is not quite a bad deal. The M is good for a daily. GT-R will be your daily or you have another for daily? GT-R is not good for daily IMO.
2005 Carbon Black M3 Convertible
2005 Mercedes-Benz SL55 AMG (SOLD)
2007 Ferrari F430 F1
2012 Nissan GT-R Black Edition