Our 2005 E83 X3 is at 116,000 miles, its 3.0 engine is in perfect shape and I have replaced most important parts like brakes, suspension, engine plastics.
Unfortunately, it has been rear-ended twice and my wife is concerned about its structural integrity so we are considering replacing it with a newer model, used though.
Which engine would you recommend? :

1. Early 28 model with N52 engine.
2. 28 model with 4 cyl turbo engine
3. 35 model with N55 turbo engine?

I have a bias for NA I6 engines and ease of diy repairs so the N52 is my preferred option but not sure about a Magnesium block and electric coolant pump.

Does the N55 have the HPFP problems as the N54 engine?

Thanks in advance for your reply!
JP