Welcome aboard!
A few thoughts - Go gradual. Most people who have a number in mind aren't necessarily aware of what 450hp in a Z32 feels like (nor are they ready to use even HALF of it).
Most people also get butthurt when they hear that, but we're not here to blow smoke up anyone's butt.
Sounds like you got a real collectible there, so take care of the necessities first. Even in pristine condition, it's going to have issues (mostly from LACK of miles), so get it in 100% perfect factory-fresh condition first.
Adding power gradually ensures that you don't wind up with a pile of expensive parts that don't play nice together. Been there, done that, more times than I care to admit.
Beyond that, enjoy being the curator of such a rare beast, and let the experts here guide you through the fun that is Z ownership!