Diesels are all I own now including a 335d and Ford F350. The main issue with the X5d is complications in the urea/after-treatment system. It is an advanced first gen system that can be problematic and expensive to diagnose and repair. Today's BMW's are complex to begin with. Delete that junk and the d is one of the most reliable, efficient and powerful vehicles on the road IMO. 148k and no issues here. I realize modifications are not for everyone, just my 2 cents.