There are two versions: The dampener version and the non-dampener version. Apparently, only cars with manual transmissions had the dampener.
When I changed mine on my six speed graphite, the new one had no provision for the dampener, so I unbolted the dampener and threw it away.

Later, a forum member here told me that if you order the part for the 2003 SLK320, and specify manual, you get the right part. But ordering for a "Crossfire" means you only have one choice - which is why we do not order "Crossfire" parts, we order 2003 SLK320 parts.

But again, my car ran fine without it.