Your situation is exactly what I did. I tracked (HPDE stuff) an E36 for years and needed to step up to a more competent car before I pushed the BMW passed it's capability and into a wall. So the NSX was a great choice for me. It's a more capable car but also requested more from me as a driver. I paid
$20K for a 1991 with 117K miles BUT it came with VERY little service history. I'm a fair mechanic so I checked all I could visually and put it through it's paces on a test drive and didn't find any big issues. The records that did come with the car, and from the local Acura dealer, showed the car had some upgrades ($12K from RM Racing) in transmission (short gears), sway bars, wheels and tires (bigger and wider), headers, exhaust, etc., with standard oil changes, so I was hooked. I like my cars right, so I found I would need (all prices are approximates):
TB/WP/TENSIONER/HARMONIC BALANCER $600
HOSES $200
CCU REBUILT $180
SUSPENSION STRUTS $200 used from a 2000 w/15K miles
MISC GASKETS (Valve Covers, Spool Valves) $150
ALL FLUIDS $150
BRAKE MASTER CYLINDER $180
(I still find little things to keep me learning about the car)
I did most of the work myself and enjoyed most of it. I have about $2K in parts and feel the car is in fairly good mechanical condition (clutch could go anytime - I don't really know of any good tests). I have tracked it once so far and it's a joy to drive. This car begs to be driven and driven fast. I probably paid a little too much initially but I wanted a Black with Ivory interior, and there it was not 20 miles away.
If you love cars and driving, you'll love this car. Whatever year you buy, have fun and let us hear about your experiences from time to time. We like to hear the excitement, it reminds us of how we felt when we woke up the next morning and looked in our garages just to make sure it wasn't a dream. Happy Motoring!