If concerned about shortening the life of anything, maybe best to keep it stock. Or possibly do a trans tune to eliminate the most annoying part of these... the shift behaviors. That's my thinking though. I'd love a trans tune.

Though our X is still behaving at 165000 miles so it's easy to not jump on the delete band wagon. *fingers crossed* So far only emissions stuff to get replaced were EGR and both NOX sensors. Like you, I would also like to keep the complete system functioning as intended as the diesel smell would kill the car's appeal quite a bit.

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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)