Is this not a US model? I'm assuming that this is a 124 car.
The 124 cars as well as many MB's have an inordinate amount of body roll. It seems a little strange at first, but after driving just a little, you will probably not notice it. In spite of this excessive body roll, the cars handling is quite precise and predictable.
Even so, I did something about it on my 300E. I put a set of Sportline sway bars and performance shocks and struts. You can take this one step further by putting the Sportline springs on, which are stiffer and shorter. The springs will lower the car and I expect do away with much of the roll. I am quite happy with only the bars and shocks.
The front sway bar and shocks at all four corners are pretty easy driveway work. The rear sway bar is another thing all together. I had to lower the rear suspension unit considerably in order to snake the old sway bar our and the new sway bar into place.
I expect that after you drive it a little you will hardly notice the body roll.