Digi,
Thanks for the info. I don't really monitor the X5 board - maybe I should - and didn't know about the letter.
Martin Birkman gave an introduction to dealers about the X5 4.6 that is available on the web at
http://www.liveautos.net/public/bmw/. Perhaps you have already seen it. It says what your posting says - just in Martin's words.
Personally, if one can get past the automatic transmission and SUV characterisitics, the X5 4.6 is an M car but, as a marketing guy myself, I understand not using the label.
In my personal situation, it is wonderful to have an X5 4.6 for the travelling with two dogs, runs to Home Depot and grocery hauling and the M5 for those days when an X5 just isn't enough.
Bob