I've been researching the whole sunroof maint thing.
This stuff Part # A 001 989 50 51 is damn expensive!
MSRP is like 40 + Dollars and you can get it online at some dealers for around 30+ shipping.
A friend who owns a detail shop mentioned the 303 stuff.
They make what called "Areospace Protectant".
303 Products Inc.: 303 Aerospace Protectant
which is the stuff you would use for the "rubber" seals.
Well if you read their lit, it's actually a different compound.
I wasn't convinced it would be the same as the MB stuff, so I called.
I spoke to a tech guy who said, the 303 stuff soaks into the
seals and restores the normal surface tension, and cleans the rubber, and should result in correcting the sqeaks.
But the MB part is specified as a lubricant.
When you go to order it from a dealer online it's referred to as "grease" but from what I've read, it sounds like it's not grease per se.
Also people have recommended the "Wurth gel stick" I think it's called.
If you go to 303's webpage you can get free sample of everything for $5 shipping, including a 2 oz bottle of the Aerospace Protectant
WHAT EXACTLY IS 001 989 50 51 ?????????