A slight nit with that last statement. In general it is correct, however, on some cars, certain modifications won’t hurt (and may possibly enhance) the value of the car. If the car is one that has a known defect, and your modifications correct that defect, then the only people who’ll complain are the absolute purists, most car collectors won’t complain a bit about the modifications at all.
An example of this would be certain British car makes cursed with Lucas electronics. Ripping them out and replacing them with danged near anything (including a hamster in a wheel hooked up to a non-Lucas generator) will make the car more attractive to most car collectors, since they won’t have to go to all the trouble to do it themselves. Now, if you chop the top, have the car plated gold, slap on some 28" rims, replace half the interior with speakers, and cover everything else with monkey fur, you’re not getting your money back out of the car, odds are, and depending upon what kind of car you do that to, may be at risk of being clubbed like a baby harp seal.
