Dont know about your model but I subsribed to http://www.pindelski.com/ specifically because I was changing my timing chain and rails on my 420SEL v8. He's got a great site for this stuff and covers both those projects with over 100 digital pics of the job. Definately worth the $30 for a year subscription. This was a new job for me so it took me a day to pull the alternator, p/s pump, distributor, deal with a few seized/stripped bolts and concoct a tool to pull the timing rail pins and install the new rails. Running the new chain through took only 30 minutes working with a buddy. I also spent $3 for insurance by buying an extra master link that comes with 2 more c-clips. those clips are so small and easy to drop and loose.

good luck