I've driven a few while looking to buy. Most were stock, some lightly modified and one was supercharged and had major suspension work. All were early model hard tops-I don't want a targa.
Honestly, I don't care what out performs it. It's an NSX. They are close to appreciating and will soon be one of those cars that you wished you had bought when you could have. The NSX is the pinnacle of my car lust and has the right combination of driveability, affordability and serviceability. Yes, I can buy a Ferrari, or Porsche or Lotus instead but none of them push my buttons like an NSX does.
You are correct about the cockpit, they are a tight fit for me at 6'0" without a helmet. No idea how I'd fit with one on for a lapping day or autocross. I'd worry about that later, probably a modified stock seat or an aftermarket bucket only for those times. The black interiors are bleak, like a stock Miata. The ivory ones are more interesting and enjoyable (to me anyway, I had a tan interior in my Miata FWIW).
A stock NSX drives very benignly around town. Aside from all the stopped traffics, pointing and picture taking, it's like driving an Accord and it could easily be your daily driver. Modified ones can be rough riding and twitchy or just a bit harsher than stock. It depends on how hardcore they are set up. I'd suggest some mild upgrades to the shocks, springs and bars just to freshen the car and firm things up. You probably don't want to drop the car much or you'll never be able to navigate most speed bumps, curb cuts or the like.
Can't vouch for how complicated the NSX suspension is or how much after market parts cost but I know that most stock maintenance parts are still available from Acura at a fraction of Ferrari/Lotus/Porsche prices. Honestly, I'll let the dealer service my NSX when I get one.
Prices are all over the map. I found almost the perfect one for me last summer. Silver '91, ivory interior, totally stock (still had the car phone installed), low miles, most records with a good service history and priced right. But, it had some minor paint work that didn't quite match and the transmission was notchy-probably bad synchros, not in snap range. At just north of $30k I probably should have bought it but decided to wait until I finish with grad school, refi my student loans and see where my financials fall. I graduate in just over a month so I'll be back in the market soon and will let you know what happens.