Might be time to raid the junkyards, or start buying parts cars? It may save you money in the long run with old cars is my experience.

However, the fact of the matter is that these cars do not need their belly pan encapsulating kits. I worked on a friend of mine's '98 E300 with only 70K miles on it, and it's belly pans were long gone a few years ago. It's engine compartment looked like a salt-mine of corrosion too. It had spent it's first 10-years or so in Chicago, IL.