Nismo if you want to track it without going into mods immediately (of course except for brakes, tires and stuff that every car needs for track abuse).
If you mod the car anyway with a new suspension and exhaust, then the Nismo is almost pointless.
My only reasons to not go Nismo was the colour options and the lack of an AT here in Europe. And exhaust and suspension may come one day anyway.
Biggest point: 90% of the drivers won't use the full potential of neither car anyway