Thanks! That's definitely going to be M. I was impressed by the TQ and MPG figured of the E70 diesel (my bad). Was thinking the E70 M or the next F15 M but the build quality of an X5 is very poor considering all the problems I'm having with my 2012. The F10 M5 is looks like headed into the same direction built quality wise as the E70. So far I've narrowed it down to E71 X6M or the F30 M3.
Retired: 2005 N52 E90 330i Sport 6AT
Retired: 2007 N54 E92 335i Sport 6AT
Current: 2012 M57 E70 X5 xDrive35D