From car and Driver:

"Shorn of its decorative plastic sombrero, this Mercedes engine would look more familiar. It rolls out of the AMG handicraft shop in Affalterbach, Germany, and previously found work in the SLK32 AMG and C32 AMG. Both of those models have since gone to V-8s, and Mercedes has developed a new 268-hp, twin-cam, four-valve naturally aspirated V-6 for its 2005 SLK350 (C/D, June 2004). So the Crossfire SRT-6 is the last customer of a very nice hand-me-down."

http://www.caranddriver.com/roadtest...ire-srt-6.html