I cant say about the US market, but generally, here in the UK, desirability pushes up market value. the right colour, sorry color (
) factory options and up to snuff maintenance ups the desirability and speed at which a car sells also it may well command a slightly higher sale price.
aftermarket mods and messed about with cars push the value down as does an abscence of paperwork.
from 2001 to 2005 here in the UK silver cars were in high numbers, so its an 'average' colour for that year range.
yellow cars do look great but the demand on the used market is lower, and that reflects in the sale price.
a non factory stereo system wth non stanrd holes in the trim, will command a lower price than a factory standard unit that hasnt been cut about.
a factory bose system, factory crested headrests will for sure separate the car out from the crowd of available equivalents, however, heated seats may not command a premium in southern california or arizona, where on the atlantic coast they may well do.
mine has factory PSM, cruise, sport seats 18' split rims and hard top. but what is all that worth if the maintenance hasnt been kept up with ? not worth an engine that hasnt been maintaned correctly hand-grenading.
you just have to weight the sum of all factors combined, but not let an AVIC upgraded stereo sway you from the car with a mint maintenance history.