Many people will add aftermarket stuff onto their bikes. It appeals to them and they think it makes the bike more valuable.
The problem at re-sale time is, unless you can find a buyer who wants these add ons, it only makes if more difficult to sell.
Add ons are like beauty. Their value is totally in the eye of the beholder.
The buyer will start off with a high price due to the cost of the add ons.
As a rule he will sell it for much less as he can't find a buyer who shares his tastes.