It's not really a big deal, but you have to remember that even a small mistake can end up costing big bucks! The holding tool for the camshafts is #271-589-00-61-00. The tensioning rail can simply be pushed back to relieve the chain tension, so there's no need to remove the tensioner again. MB makes a tool for this too. It's part number is 271-589-00-31-00, but I'm sure there's an easy way to unload the chain without using this tool.

Like I said previously, it's not a hard job to do, but it's not a hard job to screw up either. For what it's worth, the MB Time Guide suggests a little less than four hours to do this job. You should consider the cost vs. risk, along with your own comfort level before you tackle this job.