If the history is incomplete you'll have to the answer to your question. The list is long if you're looking for 10 years trouble-free operation. Somewhere on this forum, there's a list of possible items.

Your main decision should be who is working on the car. DON'T take it to the average guy/garage. Mechanics with NSX-experience are rare and they WILL take the engine OUT. Not for the case of doability but for peace of mind and less probability of errors. It's no fun doing a TB with the engine still in place. Have a look what Kaz is doing in his Blogs (at the top next to forums).