SilverSi
I'm a power freak - the SD was the engine in my opinion, as I had an 3.0d E90, so fully aware of what that engine could do (GREAT engine) but I wanted that little iddy biddy extra turbo charger
Not really opened the car up as yet, still playing it by ear and being careful, although the weekend may change this as the motorways are all involved!!!
At normal running speeds no real difference, it does make a nicer engine growl then the E90 but honestly I won't know till I really go nuts with it.

How are you breaking yours in?

Air con on air con off, was doing that last Saturday as I was stuck in London traffic. I was a little horrifed with the mpg counter touching 19mpg.......but this was all start stop.
Must also admit though the X5 heats up like an oven without the air con on - whew!!!!