FWIW - here is my two cents.
Personally, I think ultimately they will go down due to the release of the new model - with these caveats:
- I think that prices in the last two years have gone up due to hype about the new model and people remembering how much they liked the old model when they were younger.
- Prices have also gone up in recent years due to improvements in the economic situation as a whole...whether this is sustainable is questionable
- Prices on MINT, 100% stock (never modified in any way) examples will probably continue to rise slightly due to collector status
- Prices on modified cars is likely to stagnate unless just the right buyer finds just the right car for them. There is less of a collector market for modified cars...these are meant to be driven and enjoyed.
- I think if the new NSX is a huge flop, first gen NSX prices will continue to rise. I think the chances of the new NSX flopping is very slim given how much Acura/Honda has invested in it. It may not be a game-changer like the Mclaren P1 or the new Porsche hybrid supercar, but I think it will make a similar impact to the Lexus LFA at its time of release (which was neither the fastest or best performing supercar when it was released due to its lengthy development time).
- I think the most likely scenario is that prices will take a slight decline (~10%?) due to positive feedback and interest in the new generation NSX.
- Some first gen owners may elect to sell their cars to buy the new generation, which generates more supply than demand.
- I think a very very small subset of the population will opt to purchase a first gen NSX due to renewed interest in a "purer" driving experience, but chances are people who would opt for a first gen for this reason would have already bought one in the past few years as news of the new NSX was released.
However, if all of a sudden there is a huge crash at NSXPO and the supply of NSXs is greatly diminished, then of course prices will shoot through the roof!