grand nationals are only going to become more and more rare - an awesome vehicle and a milestone for buick - i say if you have the money have it restored and keep "your" car forever - when it comes to listening to your head or your heart: you can take meds for a headache, but heartache is not so easily cured...
as far as getting your money back out of it goes i would say dont worry about it - sometimes with cars like that you would be surprised - its not like they are making more of them