The 4 piston design is mostly used to equalize brake pad wear by spreading out the braking force. If the piston sizes are staggered, taper wear of the pad will be reduced.

See the caliper section here https://www.motor.com/magazine-summary/performance-perspectives-july-2008/

Floating calipers have a piston or pistons only on one side of the caliper. I doubt the E300D has a floating caliper, it probably has a fixed caliper with a single piston on each side.


Increasing MC piston diameter increases pedal effort / reduces pedal travel. This is rarely done in the field and the only one that comes to mind in the 70's Porsche 914-4 that had a small MC bore for a light pedal making the brakes difficult to modulate due to long pedal travel. The MC from a similar year 911 does the trick ( along with removing the rear brake bias regulator )

The on your E300D , only " fix" may be to use larger rotors / calipers and proper MC from a late R124 SL600 but this would be more work.

I've had my 97 SL320 on a couple of time trial track days and can easily cook / fade the brakes. The car slows / stops fine on the street but multiple race track brake applications take their toll as the R129 " Sport Licht " Is only semi sporty and at 4,100 Lb makes a mockery of light.