I thought MDM was a less intervening version of traction /stability mode? Its independent of DSC????? If so, then with DSC off and MDM on, it would let you spin the tires pretty much unlimited until it detects that you're going sideways, then intervenes?
If MDM is on, then DSC is not off. In terms of intervention: regular DSC > MDM DSC > DSC off (zero intervention, of course)
