Judge AR

Back to the OPs original question I'm not completely familiar with exactly what AWD systems BMW or MB actually use, or an expert on AWD, but this goes back to the old Torsen vs. Haldex question. The majority of AWD systems out there are similar to the Haldex AWD (used by Audi/VW in a few of models, A3, TT, R32, Passat, Tiguan, and a few others I'm sure) and is/are reactive systems, and always one wheel drive biased (Front, or Rear). Now the vast majority of the Audi line-up including the allroad uses Torsen AWD also referred to as true Quattro and is 50/50 proactive system (I do believe Subarus is one of the few that is as well. Basically meaning that with and Audi (torsen) or a Subaru your getting power to all four wheel all the time (usually in a 50/50 split) that will adjust, while with Haldex and most other AWD systems its usually completely FWD or RWD until the wheels begin to slip and then reacts 100/0 or 0/100, they also usually cant go past 50/50, meaning if its fwd biased it can do 100/0-50/50 but can't go to say 40/60. Their has been much debate as to which is truly better and in what circumstances they both have their strength and weaknesses, and it would be wise to do a search an read up on both to get a better explanation of each.