This seems to happen to the W202 bodies as well. One reason I sold off my 17" wheel combo was the inability for the factory bushings to handle increased loading thanks to the larger wheels and tires. Luckily, the dealer covered the repairs under warranty.
I went back to the 15" set up, but might "tinker" with some mild 16" set-ups to try to get a bit more grip without compromising suspension tuning. I did install the AMG suspension, and would like to take advantage of it a bit more, but huge 17 or 18" boots are not needed on the C230. It's only got 150 ponies.
1998 C230 "Black Betty"