Originally Posted by '10Anamoly

Adjusting A/F trims is good but I heard there is a lot of advanced timing in the tunes as well. Per previous discussions in posts, the A/F adjustment is safety only really not much power there. The timing is what is bringing the gains. I'd figure that the NISMO tune might also adjusting the valve timing a bit to properly get more out of the system, aside from just advancing the timing.