Of the E70s, the 3.5i has the least issues. You will love the 8 speed automatic. It is really nice. There are no specific red flags with those. Just higher failure rates in general when compared to a Lexus but you already know that owing an E53.

What is going on with your GM transmissions? Our 03 X5 w/ GM is doing better than our 05 ZF. Both are 160k+ miles. My father wants me to pick one of the two to give to my 16 year old daughter.

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2009 35d, 2006 325i & 330i