KEEP THEM!
You should store them fo sho!
-If you sell your car put the stock parts back on and sell the aftermarket parts. You will get more $ this way.
-If your aftermarket part gets damaged or you want to change it out you have a replacement on the spot and can take your time replacing it.
-If you have financial problems and need some money, BOOM, sell some parts.
You get my point. There are many reasons to keep your stock parts so choose wisely!