toaster, it appears you got "toasted". A MB dealer performed a pre-purchase inspection and failed to mention the rusted doors. Repairing rust can be a never-ending battle. I wouldn't consider buying any MB with even minor rust issues. In the long run it may be best to replace the doors with ones that are in excellent condition and rust-free, but first you may want to get a professional opinion from a reputable body shop that specializes in MB repairs.

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Fred Hoelzle