The last time i saw a UDOT sell for its lowest price was 2009 - someone posted on RGP, a non working one for 900 or so. Sold in three days. This was before the film. I kicked myself for passing but at the time i was pin crazy.
Since then, when they even come up for sale, 1200 - 1500 easily, and lately, there is ALOT of demand for these. I just sold an EDOT and had inquiries, with around 5 lookers passing because they were holding out for a UDOT (space + cheaper).
If you can convince your friend 400, the best to you, you found a great deal. But i would suggest leveling with him and offering a little lower than value (explain it saves him trouble), because if he tests the waters and it goes on CL, it wont last more than 24 hours at sub 1k.
Oh - as far as fixing them to run - not much to it (if i could do it with the help of KLOV of course, anyone can).