I know it seems easy but.....
The balancer notches that look like they line up with the last water pump bolt do not on the 560sl. I know, cause I spent a couple of hours with a stubby wrench in my hand trying to get the last one out only to realize that the harmonic would have to come off after all. Doubles the repair time. One guy recommended using a stud and a nut on the replacement for ease of use "the next time."
No that big a deal once you know what to do, but for a first timer, kind of intimidating. Shop manual I believe calls for 6 hours, MB guy tells me that the experienced guy with all the tools can do it in 3.5. Not sure of what I was doing it took 1/2 of Sat, 1/2 of a Sun.