I've been through a few cars in the last couple of years and from what i've found, most optional extras dont add a great deal to the selling price - if any. Its just makes them a little more desirable/ easier to sell if the price is right - providing the buyer wants it.
My mint 09 BMW 335d which was 6 months old when i sold it had about 3k's worth of BMW Performance parts (fitted by BMW) prob gained me £500 tops.
The C63 i bought came fully loaded and again that cost me about £500 more than a lower spec, similar miles model for that age.
Unless your buyer is very specific, sometimes less is more in terms of resale value. Just my 2 cents