[blau911]

$12,000 for a rebuild on this car's motor is too high. $12k would include removal and tear down which has already been done. In addition, if you have any decent knowledge of 911 motors you should be able to inspect the parts and see what machine work needs to be done (i.e resurfacing cams, crank, valves, valve seats etc..) Tranny is missing as well. Is that with the car? If not, add on another $1500-2500. for a good one.
The body looks nice, but based upon the few photos, it is hard to tell to what extent if any there are rust issues. Look at the trunk area closely with the carpet and spare removed, especially the front pan, the smugglers box, the batterie boxes. Get a closer look at the door jams, pull up the rubber seal around the trunk lid and see what if any rust is there. If this car has been anywhere but Arizona, there is sure to be or have been some rust somewhere. One of the photos of the passenger side door shows that there is substantial peeling of paint behind the passenger door handle. Is that surface rust?
As regards value, a nice 2.2T coupe matching numbers, original colors, good running condition is worth $30k+ now. Motor, tranny rebuilds, and a good paint job could easily set you back $15k.
So if the seller is looking for $15k, you are most likely looking at spending a total of $30k to make the car nice - and that does not include your time and effort...