Sell or keep?

[Titan]

Having just bought a Golf automatic for my Mum, her A8 (FL 2.8QS that once belonged to The Laird) is surplus to requirements. I've got it in storage and wonder if I should just lay it up and keep it? It's probably not worth much, hence my thoughts about storing it for a long time but I'm aware it's not an S8 so will it be worth anything in the future? I've seen Audi 100's and 200's being sold for decent money recently, even basic models, so it might be a worthwhile gamble.
I think the A8 will be a future classic but who knows. This all stems from selling my Audi Coupe GT about 12 years ago for buttons and now wishing I had kept it for all I got for it! I didn't have the space back then but I do now so should I keep the A8?