Man of Honour
Though I think it shares more underneath with the 370Z than the GTR the auto on my Navara (3L V6) is reasonably smooth and responsive - no 1-2 second lag pulling away from the lights or clunkiness. The only time I've noticed it struggling is when going up steep hills at around ~45mph or down long hills at ~30mph where it can't quite decide which gear it needs to be in if I'm trying to stick to the speed limit - fine if I go a little faster :|
I'd imagine it's the same Jatco or very similar to the one in the 370Z, the 370Z and Q50 use the same auto box