While everything posted so far is essentially correct, it may not be the biggest cost of owning an NSX. For me the biggest cost is attributable to following the posts on this website. Before I started following the threads on NSXPrime, I was happy with my stock 91. Then I started getting a bug to change wheels (Work 17”-18”), exhaust (Comptech), shocks (Bilstein), swaybars (Dali), stereo (Thunderworks) and supercharger (CTSC). And although the transmission was not giving me problems, it was in the snap-ring range, so close ratio gears… and since the transmission was out, new clutch. And next week I will have Comptech headers installed.
So, it may not be the reliability, maintenance, or rear tires that will consume those extra dollars, it the desire to upgrade and personalize your NSX. The car is a work of art and worth the investment of time, effort, pride, and more than a few dollars.