Originally Posted by PTinVT
The other point I would offer than is that BMW x-drive is a RWD-based system, while Audi's are FWD biased. BMW puts all the power to the rear and diverts to the front on slippage. It's quite a thing, especially when you put it in DTC mode, you can drive it like an old American car in the snow, powering/drifting through the turns vs. pulling/compensating for where you wanted to go. If only you could test drive both in a snowstorm (and know to press the DTC button) you'd be sold.
again... good luck with your purchase decision. Audi is fine too.
I'm afraid you have it backwards. Audis old system was similar to what you are talking about but BMWs system has never been like that. unfortunately, compared to Audis quattro the BMW x drive is antiquated. I imagine they will make some changes to 2013 to keep up with S4.