I started the POR15 process but was not comfortable with the results after using the METAL READY. By then my time had run out and other priorities were calling. I went through the instructions again and also called Customer Support so I think I have a better handle on what to do next time.

In the mean time I was curious about what Mercedes demanded for surface rust repair and was essentially told that it depends on the paint manufacturer. Since this car was prepared/painted with Glasurit products I tracked down a local contact (Glasurit is owned by BASF) and he was fairly helpful. These are the products he recommended to follow closest to OEM metal preparation and painting:
Glasurit epoxy 801-1871 (used by MB on bare metal for warranty repairs)
Glasurit HS Primer 285-50
Glasurit Stone Chip Protection 1109-1240
Glasurit 55 Line base coat
Glasurit 923 series clearcoat

The rep couldn't recommend POR15 because there is no knowledge of compatability with Glasurit and that it is not a Glasurit product. Another auto enthusiast friend also suggested that I stay with an epoxy repair which, I assume, implies to not use POR15.

So I have a dilemma. Using the POR15 process looks like a job that I can do myself but will likely not match OEM or meet long term corrosion protection needs (unsure of compatibility with surrounding paints and anti-corrosion coatings). The Glasurit/epoxy approach appears to be more complex and more expensive (ie body shop) but offset with more long lasting and better visual results (compatible with surrounding coatings and using well-researched products).

What more should I find out? Are my assumptions correct or am I misleading myself? Your comments?

Thanks,
Paul