I’ve just upgraded the sink in our 2018 320S with a Sofitel-style stainless sink and glass lid. When searching the forum for any information, I found references to other members having completed this upgrade but no details, so I thought it might be helpful if I posted my installation experience.
The new sink is a Dometic / SMEV VA8005 which I purchased from Amazon for $219 + tax. Installation took only about one hour, although that was made easier and quicker because I had previously fitted a Hepvo trap and flexible connector for the existing sink.
Removal of the existing sink was easily accomplished by unscrewing the four corner clamp wingnuts and breaking the fine caulk bead. The faucet was then easily removed from the counter. Since they both fit, I chose to transfer the drain and faucet to the new sink.
Perhaps the most critical part of this upgrade is the precise measuring, marking and cutting for the enlarged opening of the new sink. There is minimal room for error. I used masking tape to map out the opening. Keeping the front edge of the existing opening I cut the sides, back and corners. I offset the new opening slightly to the left, to allow for the close proximity of the right inside cabinet wall and used my cordless jig saw for the cuts.
Since part of the existing faucet hole is exposed, I used epoxy putty to fill it (although the dark gray of the putty does not look so awful, I do plan mixing a little acrylic paint to match the counter top). After checking for fit, the sink can be positioned and anchored down with the corner screws which are accessible from the top by removing the four rubber pads. Note, there are four tiny clamp extensions that should be fitted before dropping the sink in the opening. Once the sink is secured the water lines and trap can be connected. The final step is to run a fine bead of caulk around the sink (I used GE clear silicone).