I don't even like Nissan, but I do admire the Z and the GT-R.
When datsun released their original Fairlady Z sports car in the 70s, it destroyed the euro competetion in the US.
The GT-R then (1989) and now (2009) has always been the new yardstick. When it raced and won in many lopsided races in late 80s/early 90s, the GT-R was slowly castrated and then outright banned.