It seems like I read somewhere that the X-Drive goes into rear-drive mode above 120 mph? So there must be some type of setting/logic with everything intact and rear wheel drive only.

It would be nice if you had the option to run in rear wheel only mode with DSC and ABS functional still. Maybe a fair weather/summer mode for a different driving dynamic. That being said, pushing the envelope in an X5/X3 could get you into some trouble. There's a lot of mass up high in these machines, and even though its a pretty stable platform, my guess is it relies more on the x-drive dynamics more than you know in a performance/saftey function.

Honestly, if your driving within reason, and not sling shooting a 60 mph power drift on an on ramp, probably not that critical. However,the AWD with DSC is like wearing a safety belt. You put it on because you never know when your going to truly need it. A highway speed maneuver on the interstate avoiding a collision with an object/person/animal/another car, might have two distinct outcomes based upon the driving dynamics you choose, if you had the choice. Just thinking out loud. Maybe mute the system and let it do an override if a set of conditions is sensed, kinda like hitting the DSC button. Its working in the background, ready to intervene when called upon. Just an idea.

The other side to this option would possibly allow for slight enhanced economy at the ol' gas pump.

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2005 X5 3.0, 6MT, Alpine White on Truffle Brown, Sport, Preim, and Cold Weather, Alpina Stainless Headers, AFe Intake, UUC SSK, OEM 87's, 3.64 Differential Swap,Performance Modified Euro 2 Tune, UUC LTW Flywheel and HD clutch, Bilstein B12 Suspension kit
Future mods ZHP/Schrick Cam Shaft upgrade, Operation code name:Doppelschrauben-Kompressor

Wife's Ride: 2011 e70 X5 351 M///Sport.

Also in the fold: 2004 X3 3.0, 6MT, Black Sapphire on Terracotta, port, Premium, Cold Weather.