X35d is great for travel. Find one that has had the egr done, not that it's crazy hard, but it will save you the trouble for a while. Glow plugs and the associated module like to fail, again not too bad a repair (~$650 all in DIY). Emissions stuff is a "cross your fingers" set of items. We've done both NOX sensors and went used, looked for newest part number we could find, so that was only $90 for the pair.

We've put $2500 into ours over 2.5 years after a $14k purchase probe @132k miles. It's got 165k+ on it now and, since doing a complete front suspension, feels like a much younger vehicle. Finding one that was well maintained is key. We bought the dealer's personal vehicle and spoke to the shop who maintained it before purchase.

Not sure if our experience is typical... But we wouldn't hesitate to buy another x35d should something happen to this one.

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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)