I had a similar issue with a 320, the coupe and cabriolet exhausts are different, but only slightly, it needs to be bent a bit to go over one of the 4 strengthening bars that a cabriolet has and the coupe doesn’t.
Mercedes did supply one for the 320 at the time but the price was a joke, a local motor factor could supply but the quality was questionable in their opinion.
I also recall finding one on eBay Germany, but in the end, the garage made the coupe one fit that I had bought in error. That being said, the 320 and 220 ones are different, so maybe the mod wouldn’t work in your car.
