 Picked up a low mileage 07 M5 after reading some tough reviews on fuel economy and terrible SMG transmission.  Don't beleive them!  This car is a drivers fantasy car...the motor and transmission are incredible and smooth, you just need to invest some time and figure it out.  I am getting 19mpg sriving 80mph with "power on"...it'll go from 50 to 100 fater than I can write it, the paddles/F1 shifiting is perfect.  I have a 911 and a CayenneTurbo...love them both - this is better.  If you love to drive, find one of these M5's and own it.  Also helps if your brother is a state trooper, you will get in trouble, promise.