I have to think that the eBay reserve price is the buy it now price - $43.9K. So you're going to pay that amount, plus you're prepared to spend another $5K-6K out of pocket to possibly bring it to "normal condition?" So the bottomline is you're prepared to spend $48.9K-49.9K, so it appears.

Alternative 1 - Get a CPO. There are plenty of $48K-49K X5 4.8i CPO's sitting out there.

Alternative 2 - Buy an '08 at 0.9% @ 60 months. There are dealer incentives to move 2008 X5's which should translate into a big time discount. Unless you're a cash buyer, you're likely going to get somewhere between 4.5-6.5% financing on the eBay car or an '07 CPO car, so there's another couple of grand savings on finance charges. There are over a hundred new 2008 X5 4.8i's sitting in Florida still unsold.