Johnny, you found the best place online to ask about the NSX.
You mentioned you wanted the latest model year, may I ask why that is?
If it is cosmetic reasons, the 02-05 MY have the same aesthetics. 91-01 are almost identical but a few have done "02+ conversions". So keep that in mind.
If you wanted a late model year for lowest mileage/wear/tear/maintenance reasons, consider this. Many NSX's of all MY have been well cared for, scaresly driven, and maintained. So I wouldn't limit yourself to the latest year only if that is your goal, a clean NSX. Also remember even the "newest" are ~10 years old, these are older machines no matter the MY.
If you wanted the latest MY for powertrain reasons, as you mentioned, the two powertrains ran from 91-96 ("NA1"), and 97-05 ("NA2"). 3.0 L 5 speed 270hp 210 lbft, and 3.2 L 6 speed 290hp 224 lbft respectively. There's also forced induction options for both if you NEED more power.
If you wanted a T-Top, you're MY's of choice are 95+. Note that coupes after 94 are few and far between.
If you wanted the latest for safety reasons, I belive 93+ came with a passenger airbag, but all came with ABS and TCS. And the design barely changed for 15 years, so that helps me sleep at night knowing the 91's meet 05 saftey stds.
I can't speak for the 6 speed, but the 5 speed has fairly tall gears. Which some like, some do not. I like a long pull from ~40 km/h to well over 100km/h in 2nd hehe.
My advice: NSX's come in all assortments, milesages, conditions, aspirations, colours etc. SO, pick your favourite colour and go from there. Some colours are only offered in some MY's, so you may be restricted by that means.
If you like black or red, you've got the most flexibility
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Enjoy your search, it's half the fun! Oh, and be patient
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Cheers,
Lucas