I can enthusiastically recommend colorplus.com for MB leather (and I believe vinyl) dye. I've used their products for years. You'll get other recommendations too, but the unique thing about colorplus is that they stock standard MB colors, so you don't pay extra for custom mixing. In my experience they've matched the existing dye perfectly. They also will send you a very nice brochure describing how auto leather is made, and step-by-step instructions for re-dying it. I've done both my driver's seat and the steering wheel with good results.

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Steve
'93 400E