Mercedes has only used timing chains. They have never used belts.
The C220 is a nice car, but underpowered, with a slightly cramped rear seat. My mother had a 95 C220, and she drove it for 150,000 miles with no problems.
The six cylinder and four cylinder engines rarely, if ever, need a timing chain to be replaced because the chains are very short and don't stretch.
The M116 and M117 V8, like the engine in the 560 SEL, do require a timing chain replacement.
While it may seem an unnecessary expense to replace the timing chain, the V8's, like the 560 SEL, are extremely durable engines that will probably last longer than you'll ever want to own the car.
2001 E430, Bourdeaux Red, Oyster interior.
1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".