I've heard of several fellow CLS owners who claim to drive like grandparents and have their tranny die. One mother of three with a TLS who didn't even know it was an "S" had hers die after 14k.
Seems to definitely be a hit-or-miss. Some have changed tranny fluid at 15k only to have it die at 16k, while others have never changed in 30k, go to the strip every weekend, and have zero problems.
:dunno: Mine died at about 23-24k - I changed the fluid at 18k, but I autocross occasionally.
YMMV.