Be sure to check the warranty fine print. Look up the warranty company's track record as well. I find most aftermarket warranties to be crock when it comes to major repairs.

Unless they can show recent work, the 08 WILL need valve covers and possibly valve stem seals. When you do the walk around, start the truck and let it sit there and idle for the whole walk around (15 minutes should do it). Then do a hard acceleration and if it smokes white... that's a good indicator (not proof positive, could be vacuum leaks, CCV, etc) the VSS are in need of work. $3500 job quoted here at an indy. Then you have the entire cooling system and front suspension that will need work around 100,000 miles.

Not trying to dissuade you, I love BMW's, but go in eyes open. Sometimes these will spend quite a bit of time in the shop. But nothing drives like a well-maintained BMW (insert fan boy remark here).

__________________
2005 X5 4.4i Build 04/05 Maintenance/Build Log
Nav, Pano, Sport (Purchased 06/14 w/ 109,000 miles) (Sold 8/15 w/121,000 miles)

2006 X5 4.8is Build 11/05 Maintenance/Build Log
Nav, DSP, Pano, Running Boards, OEM Tow Hitch, Cold Weather Pckg (Purchased 08/15 w/ 90,500 miles)

2010 X5 35d Build 02/10
Nav, HiFi, 6 DVD, Sports Pckg, Cold Weather Pckg, HUD, CAS, Running Boards, Leather Dash, PDC, Pano (Purchased 03/17 w/ 136,120 miles)