Having done a dash removal on a W201 this past summer, I can offer some general suggestions:

1) Go slow and give yourself plenty of time. For a "first time" DIY home garage job, it's easily a whole weekend job to R&R a dash. It's also important to go slowly since it is very easy to scrape, ding, and otherwise injure other interior parts during this process.

2) Although MB's wiring and vaccum connections are very well thought out and usually have unique fasteners, use a digital camera or very good notes to ID connectors, harness locations and details. Don't trust memory.

3) Before undertaking the job, consider everything else you might want to do in there. Change the panel light bulbs? Add an upgrade? How's the heater core?

4) Plastic bags with permanent marker to keep track of parts.