Originally Posted by dchao
RWD + front engine = tendency to understeer.
This is why xDrive is useful, it will brake inner wheels and put more torque to the outer wheels, and therefore, dial in some over steering.
xDrive will make off-the-line acceleration faster, and cornering more secure. I think, the it should make this this M135i more exciting to drive.
RWD and front engine has nothing to do with understeer. You can set up a car like that to have no understeer at all. If the car weight is biased towards the front (like the AWD version), it will have a natural tendency to understeer.
And why is more torque going to the outer wheels with AWD? That doesn't make any sense to me.