The early cars can easily be made to be as fast or faster than the later cars and have more modification potential being OBD-I. Stock, the gearing difference is far more significant than the 20hp. The 20hp is largely eaten up by the extra weight of the NSX-T over the early coupe. The gearing is much more of an issue 0-60 than 60-160. I would love a 6spd/3.2, but the coupes are hard to find in other than the red Zanardis. Some day I may buy a Zanardi and paint it Sebring Silver.
The NSX and the M3 are surprisingly similar in their tight, direct steering feel, with the advantage going to the early NSXs unboosted steering at speed. The NSX gearbox is far superior in feel and throw to the BMW unit, even after a UUC SSK and DSSR. The S54 is my favorite I6 and the C30A/C32B is my favorite V6. Both love to rev, the NSX even more so, but with a little less low-end torque. It is nothing like an S2000, however. The NSX has decent torque.
My 1993 NSX was at least as reliable as my M3 over the same 30k mile period, with significantly more overall miles (40k). These are the ultimate Hondas and they were built to an incredible standard by the cream of their work force. These cars will be around for a long time. The NSX was a rare moment in automotive history.
Driving the two is more different than their performance statistics would suggest. I find them roughly equal at higher speeds, whether a modified early NSX coupe or a later 6spd/3.2 97+, with the M3 getting a slight nod in the 0-60. They are very competitive on a road course. I was a few MPH faster in the M3 vs. my NSX on the longer straights, but the NSX was a bit faster through the more technical portions.
The experience in the NSX is much more exotic. One is mistaken for driving a Ferrari or correctly identified as driving an NSX. Photos may be taken. People may come up to you and ask you questions about your 'new' car, whether it is a 2005 or a 1991.
The driving position is low. Your eyes are at the level of the rear license plate of the M3. Your roof line is below the side mirrors of larger vehicles. The intake is behind your head in addition to the exhaust. It is an exotic experience, but the car is so well engineered that it can do the daily driver duty that an M3 does. There are some folks that strap on the snow tires and drive them year round. But most people seem to feel compelled to limit where they drive it and where they park it. My former 1993 had 100k miles and no door dings.
People forget what an amazing race car the NSX makes. You would think the Real Time GT championships in the 1990s and the impressive GT-2 win and top 10 finish at Le Mans, to say nothing of the JGTC cars, would be enough.
Excellent summary!