Do the work on the vehicle, then when completed sell it and get maximum money outright for it and then go back and buy the 2010 outright and likely end up better off than trying to play the internal game with them.

My two cents...

__________________
Cheers!
Bill

2002 X5 4.6is
Estoril Blue, born 11/01
~226,000km's
rebuilt tranny (11/12)
New paint (8/12)
Chain rails inspected and are good (01/13)