Lovely looking car - always had a soft spot for S1
If you can afford to keep it and run another daily car you should - I cant comment on prices as not looking to buy one.
if you sell it I guarantee you will see similar cars at shows in future years and wish you'd kept it - I saw some at a show on Sunday and they really are a lovely looking car, and mint ones I would think will keep going up in price like MkI's and MkII's now.