As a relative newcomer to the site, make sure you're aware of the NSX Wiki on this site. It can be found on the red action bar at the top of most pages. It has a wealth of information on wide ranging topics and there is a specific category on "Purchasing an NSX" which has checklists which may be of value.
As an owner of a '91 that is very close to 200k miles, I believe I can address some of your questions. I bought mine in 2001 with 90k and have put on the add'l 110k as a daily driver since then. I'm a big supporter of the thinking that regular use ("exercising") is a very positive thing .. things become maintenance items not only when not serviced according to schedule but also from sitting there not being used. As someone already said, a well documented maintenance history is very important for a high mileage car in answering questions about proper maintenance.
The biggest item that people over look is the the major service interval at 7yrs/90k miles (timing belt, water pump, etc). It is expensive so people often don't do it because they haven't hit the 90k mileage mark .. but it's the lesser of years or mileage. So, if a car hasn't had a major service in the last 7-9 years regardless of mileage .. that's a red flag. Anything over 90k should have already have had the major service and probably the clutch by then. You'll quite often see prices drop after the 80-90k mark because people try to sell so they don't have that expense. Anything that hasn't honored that schedule is a ticking bomb since a timing belt failure results in very expensive damage .. although I believe that Acura did later extend the original 7 yr recommendation to 9 yrs.
Besides the major service interval, most stuff is just routine wear on things .. like clutches, tires, shocks, brake pads, etc. Weak items are the A/C evaporator (expensive); sound system (not too costly to get rebuilt); window motors (an inexpensive diy fix is available); seat wear (replacement covers are available); the ABS on early models .. the checklists notes most of these things. Parts are going to be more expensive than other Acura/Honda products so take that into account. But generally these cars are very robust and many people regularly track them. I have stressed mine in other ways that is rare .. it has survived over 25k miles of daily Canadian winter driving (snow, ice, salt, etc) at temps down to -40F so I can confidently state that it's very robust and reliable. However, you should be honest with your own situation .. if you're buying a high mileage one just to squeeze into the buying experience without keeping a reserve for unexpected repairs, that's probably not a wise strategy as you might end up with a rebuild or some other surprise despite your due diligence. There's a page on the site somewhere with a map of the US and the names of good independent shops .. check to see if there are any near you.
Good luck! It's an amazing vehicle.
