TB, I am thinking the same.
I read the reaviews about gass consumption, and like you I drive a LOT every day and the difference is about 100 kms per tank. That adds up quickly in savings.
I'm leaning towards the '04 4.4i myself.

__________________
I swear, my cars are like a girlfriend.
Sometimes its a rough ride, sometimes its smooth motorin'.
Sometimes she doesnt like how i treat her and sometimes i dont like how she behaves.
BUT at the end of the day, she loves it when I am inside her.

_______________________
'91 850i
'05 X5 4.4i
'09 Clubman S