NADA (or whatever your insurance company uses...you can and should ask your insurer the basis for comparison/payout) has no special passion for the NSX like we do...the "market/public" allows them (or whatever standard) to be the basis.
I watch this forum and the only time two people agree on a price/value is the exact time/place when a car exchanges hands...all other values are speculative.
Thanks for the responses! I verified with my carrier long ago that NADA was their yardstick, which made me investigate their values.
I disagree though about passion for these cars possibly clouding any discussion here. I agree that this site tends to attract passionate owners with high-value modded or all-OEM examples for sure, but I interpret your response as suggesting that sales as often noted & discussed on Prime are high within the average NSX marketplace and would be considered the minority or outliers amongst a much larger number of sales in the general market/public. And, even though those values would be considered astonishingly low to folk here, they would support the NADA values (or vice versa, are what NADA values are based upon). In other words, I personally think the cross section of NSX's amongst passionate prime folk is not very far off the mark for the typical non-Prime-NSX out in the wild, but I acknowledge that this is an assumption.
Assuming NADA excludes salvage/branded titles, $24k low retail for a 1991 would have to be for a real dog, otherwise a $24k NSX is pretty unheard of, at least to me, yet NADA has some data points apparently to support going down that low. And $40k for a high retail '91 seems to be much too low a ceiling for even a ~60k mile well-kept & maintained but run of the mill clean '91. Then you have Hagerty values which put a FAIR condition '91 at <strike>$48k</strike>
$28.5k, <strike>which I might argue as being a bit high if you read their definition of FAIR</strike>, up to $77.1 k for concours. I'd say Hagerty is much more accurate, but then you really pay for that potential value benefit. (this paragraph was edited - I mistakenly initially quoted values for a 2001 which is between $48k to $90k+ on Hagerty).
Until someone steps in to educate us: I'll just have to remain curious over why NADA values, which my insurer would use should my NSX be totaled, are generally too low vs what I think is reality, or encompass too narrow a slice of NSX conditions. Or maybe that narrow slice is on purpose, but with no provided caveat to warn the user. I'll assume that either this gap to reality is known and is just a part of how insurance works, or that NADA has no idea of this gap and updated NSX values are just not kept up with, being a low-volume car. Haven't really looked into Edmunds or KBB nor made myself aware if insurers use them for metrics. But clearly a NADA range of $24-40k and a Hagerty range of $28k-$77k begs some questions. Maybe the only answer is: life's not fair, insurance isn't fair, and the range for a '91 is at least $24-77k across various some valuators, so pick the insurance company with range you and cost you are willing to live with & pay for, and accept the fact that NADA's range is only a partial slice of real sales.