the fixed calipers are 4 piston opposing action biting on larger rotors. If you think the W124 regular brakes are good then these brakes will make you hurt.

The reason that MB had to use the fixed ball joint arms was that the original ones did not clear the larger rotors. The cast in ball joint control arms have the joints tilted inwards a bit to make some clearance for the rotors. With such ball joints, inspecting joint boots is a monthly task and replacement of the plastic boots is mandatory at the slightest sign of tear or damage.

__________________
2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)