Interesting how the OP was replied to on mileage with a oil change, but no comments as to the type of oil or filter. ? As a new member he was correct to think the FFS would alert him to the next oil change.
You are correct pizzyguy, I do not recommend the lengthy oil change intervals, but I doubt a 8,000 mile change is very much more damaging to the engine than say 6,000 miles. I did dig out my owners manual on the CLK 500 and the recommended oil change interval is actually 13,000 miles; as to the transmission the manuals maintenance schedule called for the fluid to be checked at 143,000. The manual on our Crossfires say 7,000 or more per the FFS indicator. Since 2005 I think Mercedes has changed those recommended intervals. JUST SAYING !

jecausey3: I think most of us here try to keep oil changes under 6,000. Many use the recommended 0w-40 Mobile one oil and some have switched to 5w-40 using various manufactures. Do not use anything other than a fleece filter. The Mann HU718/5x is the common filter used, but there are equivalents available. Do not use paper filters. More information is available by using the search box in the upper right corner of the forum and using the google option works best. Enjoy your ride and welcome to the forum. We have an upcoming event at Eureka Springs, which is a lot of fun. Check out the EVENTS section for more info, meet other Crossfire owners and check out their rides.