no no no no no no no no no NO!
if u sell it provately with after-market mods or factory mods U *"MIGHT"* be able to squeeze a few extra quid.. but not alot... cos those added extras u got were for ur benefit, u cant charge others extra.. f*ck they might not want em!
Aftermarket performance mods like exhausts, wheels, headlights etc will never add value and usually lower the price people will pay for a car.
Factory extras will always increase the price people will pay for a car all the time it is worth reasonable money.
If people don't want an extra, like some people dislike leather, they won't look at you car, they will just buy a cheaper one without the extra.
For example, lets take a REAL LIFE scenario. On friday i sold my car to a bloke who paid ?300 extra specifically for factory fitted air con and cd changer. He said "this car is ?300 pounds more than another i've seen, but i want air con and the cd changer so you've got a deal".
So it seems to me that factory options hold their value and depreciate roughly in line with the car.