Hey Rob2218
I use Aerospace 303 protectant on my Benz. Someone on this message board suggested it. It's a wonderful product. It protects from fading and if the rubber is already faded it brings back its luster without the shiny, gooey mess of Armorall. I haven't used Armorall in years so they my have improved their product over the years, but I didn't want to take a chance with my first MB so I took the suggestion offered by another member of this board and I have no regrets. They also suggested Luxol leather conditioner, cleaner, and protectant. I use this product for everything leather in my car and the 303 for the rubber trim and seals. Ummm, I think you could get these items at an auto part store but I order mine on the web.
303 Products - Aerospace Protectant, High Tech Fabric Guard - World's Leading Automotive Care Products Lexol Leather Care Including Vinylex and Kozak Products
Again....and this is just my personal preference, I would NEVER use Armorall on my car because it seems to make the rubber parts gummy and sticky. Not sure if this was my experience because of living in a hot & humid climate at the time or what, but since then (about 25 years ago) I haven't used Armorall and I've never owned anything as fancy as my little SLK except my Land Cruiser but that was my Kid Cab and it was always dirty

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Hope this helps. Good Luck!