I have the rwd sapph as i dont like the way the older models drive, also owned a 500, as the 3dr will always command a higher price and just looks superb i would get it finished, if you dont like the way it drives once finished get rid and buy a decent sapph, a 2k shitter will cost you alot of money to run, wouldnt trust anyone wanting to sell one quick either, mate or not, doesnt sound right to me, finish the 3dr.
Also who re-built it, if not done properly or by your mate in his garage the first time you come on boost it will shit itself and you will have a huge bill to pay for.