If you are buying new, why are you so worried about possible trans issues in the X5/X3? You will have a 4 year warranty and the option of extending it later.

What about the MDX? I have heard that it has a great all wheel drive system, should be reliable, gets decent MPG's and so on.

I suggested the 535xi wagon because it gets decent MPG's, can haul all of your things, drives and feels like a BMW, and is fairly quick at 5.7 seconds 0-60. With some tuning it can be low 5's. It was just a thought.

Sounds like you are set on a SUV/SAV. The Infiniti is not a bad overall package, but I just can't get by the looks.