good position to be in. clean cabs will start demanding over $20 on a regular basis. but clean means no paint fading or waves in the bodywork, minimal chips, especially on the front bumper cover, no cracking in the leather of the seats that shows any color other than the color of the seats, non-faded carpet, and all service complete and current. once any of the above come into play, the price starts plummeting quickly, 4 digits at a time.
the same can be said of hardtops, though it will take a while before they start getting close to the $20k mark.
rarity doesn't demand nearly what many people think it does either. just because a car has a rare option, color, or whatever, it does not translate to a higher price as easily as one might hope. for example, the black car we have hear for sale is an early 92, complete with recessed hood badge and all that, AND has a 1 of 7 (total from all years) full leather interior. the latter was a $4k+ option. however, to most people, it only adds a fraction of that to the value of the car. rare colors are usually a negative, not a positive. it means harder to fix, and usually means poorer condition, because nobody wanted to mess with a rare color.
the market on these cars is changing. i predicted it years ago, and it is following my prediction. low mileage (sub 30k), super clean cars will see the prices go up, but not fast. middle mileage cars (45k-80k) will hold their own for a while. high mileage cars (over 80k) will plummet. cars that need work, no matter how insignificant, will see prices fall very fast, as it is an overall indicator of a lack of care. the break between the 3 groups is about $5k. it doesn't seem to matter about much else. aftermarket stuff can make a car easier to sell, but won't really raise the price much. sometimes it's actually a problem.
if you have one of the upper tier cars, and can sit on it for at least 5 years, you might make a few grand. right now though, we are still seeing the more used up cars spoiling the market. when people see cars going for $10k-$12k, they think they are all worth only that much. as a buyer they think they can haggle everybody down to that bracket. unfortunately many owners need to sell, and end up selling for a lot less than the car is really worth. that really messes things up. it's going to be a while before that really changes.