Originally Posted by FPenvy

D mode is weird in the Z for full throttle situations. like others have said our ECU/TCM actually learns from how you drive and adapts. I drive in manual only never in D mode. if I ever do switch back into D mode it will try and mimic the way I typically drive in manual.

however in D if you go balls out it feels like it hesitates sometimes on when to shift at the top of the revs. if in manual mode you decide and can hit your shift points right where you want to.

easiest way to find out the difference is go to a drag strip and run once in D and the other in manual and see the difference. I never cared enough to do this myself based on feeling how the car shifted in D mode on the road when I first was testing this out myself.