That guy who dropped the SLR plant into the SLK is some rally driver from Dubai I think. Something about wanting more power in his SLK (duh), but wanting the SLK ride around town. That SLR engine is well behind the front wheels on the SLR and jammed up against the firewall. I could see how it would fit into an SLK, but for running on a track with some turns in it, I think it'd be less than stellar.
The guy in the Enzo didn't seem to be pushing it too hard.