Ooh, something right up my alley.
Though seeing the condition of the frame underneath would be very helpful (if it sat in a field for a long time, the soft steel frame may have serious rust issues...) I would tend to agree that's a really good deal. As a reference, that's very similar to the condition that mine was in when I bought it and got it for $3k less than that in an auction. You're definitely looking at thousands of dollars in parts and thousands more in labor if you can't/won't do the work yourself (which I expect most here would) but it's still a good deal.
Actually, it's not the 5-speeds that are rare, it's the automatics- the vast majority of DMC-12s were 5-speeds. The base model was a 5-speed and the only factory option you could get was to get the automatic- and few people opted for it. Most enthusiasts actually prefer the 5-speed though since with the fairly gutless engine you need the extra gearing to get it to perform more reasonably.
The interior looks bad, but replacement seat covers are readily available as are dash pads and carpets, though amazingly it looks like the dash and binnacle are NOT cracked which is very unusual. The front fascia looks like crap (rear is removed it looks like, but I imagine it's similar), but that's normal with lots of outside exposure- I believe it was about $1000 when I had mine stripped and repainted (though I had to pull them and re-install them).
The stainless looks to be in very good shape with no noticeable dents or damage. It's not one of the really low VIN-number cars since it has an ungrooved hood and no gas flap, but if it's an '81 it's going to be a good bit lower in VIN than my '83. Honestly, VIN doesn't matter a whole lot unless it's really low and then would have the original hoods and not the most common final version. Wheels look to be in good shape, and the doors are standing open properly so the torsion bars should be at least functional.
The engine will be a bit of a crap shoot. For cars that have sat a while and worse have had people who don't understand the fuel system trying to get them started and dumping lots of 'cleaners' down the gas tank, you're looking at $1k minimum in replacing K-JET parts. Or you could go the route I did and convert it over to a carb which is much simpler and depending on the condition of the car's K-JET can be cheaper.
Bottom Line: If you want a DeLorean and have the money, it's a good deal- you just need to be aware that it's going to cost at least a couple grand more to get it fixed up and running, and if you want it looking good will probabl end up costing half again what the asking price is.
If anyone is serious about it, I'll happily answer any questions I can- unfortunately it's a 6-hour drive one-way do I'd really not be able to go and look it over in person.
EDIT: Oh, and for reference, if you take one up to 88mph at least here in the US? What's going to happen is you're going to get a speeding ticket.