I have only been for a quick ride in one 300zx that had the Sport 700's but it had a built SZ tranny and stock rear end. I have a 5spd and 4.10 gears. The car had JWT 500 cams but didn't have 2.5' intake or 58mm throttle bodies. I was happy with the performace of that car so I'm sure I'll be happy with my set up in the end.
What are your thoughts on the 1mm larger valves? I was considering them but my build is getting pretty expensive at this point. Do you have any idea what power gains you might see with them over the OEM valves?