I guess I have a couple of things to add to Todd's post.

He's exactly right about 60 series tires and a stock diff. Even with 50 series, get a 3.90 or 4:11 gear set in there. The 3:90 set is easy to find and inexpensive. They are stock on 280ZX NA's and for sale on zcar.com frequently for $200 or so. Figure on $50 or so for shipping. Oliver at zspecialties in Washington would probably set you up with everything you'll need too.

As far as Toyo's go, they are a great tire, but in my experience they wear too fast if you don't have camber plates installed. The offset bushings just don't allow enough change to be optimal for the Toyo's. If you do have camber plates, then by all means get some.

If you have a spare set of rims, get a set of Falken Azenis Sport's for practice. Discount tire can get them in a few days, and charged me $76 per tire (205/50-15) mounted and balanced. No, they're not as fast as other tires but work great for practice or open track days and let you save your expensive tires for when you really want them. A set of stock 280ZX turbo rims (15x6) or even better early 300ZX non-turbo rims (15x6.5) is good for this purpose, inexpensive, and no one will care that you have an illegal tire/rim size during practice. The 300ZX rims are ugly, but hey, at $25/ea or so who cares. If everyone is behind you they can’t see your rims anyway

Finally, Todd is right about where you should spend your prep time first. Concentrate on making your car turn and stop well, worry about engine performance next year. A couple of exceptions to that might be adding an oil cooler, a new (not necessarily aluminum) radiator and an electric fan. You really don't want to overheat a Z engine.

Ty