Well....this is my area. I own 2 currently and have owned many....on top of that I manufacture some of the obsolete parts for these cars...it's one of our specialties at my shop.
Blake was right when he said he might pay double for one that didn't need to be restored....a few things can add up quickly for these cars. 8K isn't unreasonable at all if it needs nothing or very little and knowing the history of the car and having owned it before does carry some value.
I am also one of the founding members and Director of the SVO Club of America and most of the members have modified SVOs....they still retain the 2.3 turbo but most of us really drive and use the cars as intended....there are original type owners there too but they are the minority....but at the same time are treated as equals....room for everyone.
One of the important things is the RH outer marker light....obsolete and made of unobtanium for the most part currently. NOS versions have sold for $700-$1000 but most everything else is obtainable....but start adding up the unique parts and 8K could seem like a bargain if that car is nice.
As far as most valuable....that all depends on the car....stock or modified can bring lots of money depending on what the buyer wants. Currently though for the most part it is a buyers market still but not as much as past years. I can tell you that most people become hooked once they drive one.
....and Blake....when we talked at SEMA you said you wanted one.....well, I've been contacted by a guy with a 42K mile black 86 SVO.....once I get the details I'll give you a call