I've probably done about three full-bore starts in the last year*, despite having driven somewhere around 70 cars. Other than for willy-waving, 0-60 times and blasting away from traffic lights seems a bit irrelevant to me. 30-70 is a much more relevant measurement (I'm thinking motorway/dual-carriageway roundabouts), and for that I don't expect an xDrive BMW is any better or worse than the RWD one.
Apart from in the wet or snow, which is again why I think the car exists in the first place.
Though as Leo has discovered, the xDrive does seem a little quicker to do the irrelevant sprint time. I think the dual-clutch normal one does 60 in 4.9.
* And off the top of my head, they were all in wholly inappropriate vehicles - a Mitsubishi L200 pickup was one of them!
Pretty sure Autocar roadtest for the RWD 8 Speed Auto was 0-60 in 4.6s.
Edit:
Quote from Autocar: "So even though BMW is frequently conservative with its performance claims, we were surprised when, two-up and with a full tank of fuel, the M135i posted a two-way average 0-60mph sprint of just 4.6sec."
If the same level of conservatism exists in BMW's claims for the X version it would crack that off in 4.3s... which is just ridiculous for a £30k hatch... I know it's not really relevent in the real world, but still, it's quite serious performance. BMW should let you order one without the MSport, kit in brown, with a beige cloth interior and plain looking wheels... you'd really surprise a few people in that
