Difference between X5/X6 and X5M/X6M control arms ?

[SupersixM]

As the title says, what makes a X6 control arm different from a X6M? Bushings, Size , material? After my air suspension debacle ( all good now) , I would like to change out as much suspension parts as possible WITHOUT braking the bank.

Why is it that manufacturers like Lemforder and Meyle don't make parts for M cars as they do for non M cars?

I understand that changing out the bushings is the thing to do, but if I could buy X6 control arms and change out the bushings to M car bushings, it still comes to half of what they charge for M parts. Only if the ball joints were replaceable like the bushings.