The NA is much easier in many ways to work on than the TT, but mostly in the engine bay while everything else is about the same to work on except that the TT has HICAS, and has different suspension springs and swaybars and wheel widths (stock) among other small differences.
From what you say your experience is, I'd say you would be best off getting a Z32 that is in good condition and learning with that car is it goes through it's life rather than starting with a fixer-upper.
Now, the car you pic'd seems far more than a fixer-upper, although of course looks can be deceiving. I personally gave up on my NA as a DD after 230K and a spun engine bearing because the repairs and such were becoming a consistent thing, one thing after another. This is a pretty common scenario for a Z32 that has not been well-maintained which happened because early on it ran great, and I did not do many of the things I now do regularly and ahead of need for my TT. All or many of the circuits and sensors fail or become corroded, and along with all of the other normal needs it just becomes too much to do, and to afford for daily duty. Project car status.
I would suggest reading through as many of the Z32 how-to's and builds on this site as you can to see what is involved in some of the repairs and modifications, and spend some time at Z1 and CZP among other Z32 parts sources researching the costs of some of the parts and what it costs to buy body mod pieces...it will give you an idea of the playground you are looking at playing on!
