Mercedes defuser stall system.

[Antony Snook]

At Austin Martin Brundle talked about AMG-Mercedes using a stall system for the floor. I found more data on utube the car uses dampers (kind of like shock absorbers) mounted horizontally to prevent movement from a curb on the left transferring to right. And keeping chassis in the middle from twisting (That can damage floor) There is a mass damper like the one used on the Benetton front axle with a weight to balance chassis.
At the end of the day this system that is legal lowers defuser at the back on straights. Then in turns it lifts up so the air below can react of rear wing. Only Mercedes and Aston Martin can do this as they have long wheelbase cars. The rest of the field has short wheelbase for higher rake.