Have you swapped the 3.69 stock FD to 4.08 FD? If not, then it might provide the 'bang' you're looking for at the track without the need to boost your Z (and avoid opening the can of worms that Rusty mentioned), as demonstrated in the acceleration comparison video attached to this reddit thread:
https://www.reddit.com/r/370z/commen...f_these_tests/