Definitely talk to Billy about this. You can find him at his forum at
www.re-speed.com, or over at
http://www.iwankel.com/ where he seems to spend more time.
I'm running their front coilovers, and the rear adjustable perches. Awesome!
As for wheels, I'm running 13x8 Revolutions. They fit great with the coilovers, but I might have had issues with the stock springs. Backspacing is 4 inches.
The tires I use are dirt cheap, but perform great. I consistently beat Miatas on race rubber with these babies. They're Sumitomo HTR 200s, and they're going for under $50.00 each if you shop around. The size I run is 215/50/13.
Great shots of those Z cars man! I used to be a Datsun guy before I caught the rotary bug.
You may have seen my car at DGRRX (I think you were there, IIRC). I haven't seen any FBs running a lower ride height than mine, but I could go a lot lower if I wanted to (but it is also a daily driver).