Obviously, a lot of any pricing discussion is guesswork and opinion. So here's mine, and you can accept it as such and feel free to agree or disagree.
A modded car will appeal to fewer people than an all-stock car. As a result, with a smaller market, the car is going to be worth less when it comes time to sell, than it would if it were in heavy demand.
However, I don't know that it is always true that mods are worth more off the car than on the car. I agree with Nick that most mods add little to the value of an NSX. However, there are a few mods that IMO add value, because they are considered desirable enough by enthusiasts that it won't be terribly difficult to find a buyer who is willing to pay more for them. For example, I think a Comptech supercharger, and probably[/b] either of the other two superchargers, add value to the car. How much? Well... as a general rule of thumb, you ought to be able to get 50 percent of the typical cost of such mods when new, not counting the installation labor. So that means maybe $3K for a BBSC, $4K for a CTSC.
So... it's possible that you can get the same amount of money (50 percent) back for the supercharger if you leave it on or take it off. In which case, don't bother taking it off - so you can avoid the removal labor, as well as the risk of some other problem (tuning or such) after the removal.
I don't think most other mods, including the common ones like intake, exhaust, or headers, add value to a car. I know Lud disagrees with this and thinks they might add 50 percent of their value, but I don't. That's my O.
Now, if you take the mods off the car, how much could you sell them for? It depends on the mods. I don't think you could get 75 percent of the retail value as Nick claims. (Heck, you might even be able to buy the mods new for 25 percent off retail.) I think you might be able to get 50 percent of a typical selling price though.
Wheels tend to be desirable and marketable. However, the OEM wheels/tires are worth something (depending on tread and tires, as much as $2K or more). HRE wheels are pretty expensive, so you might get more for them than the OEM wheels, but it might be fairly close.
As for other mods, it's something of a crapshoot. In making this decision, you're juggling the amount you might get for the mods, the cost of removing them (presumably the buyer pays for shipping), the effect (if any) on the market value if you leave them on the car, etc. Removing them might be more trouble (and cost) than it's worth.
FWIW, when evaluating how much this particular car might sell for, I started by considering how much a similar car (high-mileage but mint-condition '98) might sell for when stock, which might be around $49-51K, and then added for the mods ($4-5K for the supercharger, plus another $1-3K for the other mods) to come up with my $55-57K estimate.
[This message has been edited by nsxtasy (edited 27 March 2003).]
