It already has got the response I was looking for, and even if it meant who gets the least range (as we all thrash our /M's daily) to be comical, it's still interesting.
Plus, a couple of us with launch cars seemed to get lower mpg consistently, this was a relatively safe way of working out an average across other newer models.
I believe the Range is calculated on the usage of the previous 2 tank fulls, as the range only shot up to 350+ after a) resetting the throttle adapter on the same day as the cruise retrofit, and b) 2 tanks at 28+ mpg driving.
The only way I could see this thread becoming pointless is if people with different engines chime in with their results.