I am looking for the tracks or channel on top of the roof for my 144". I've called the mercedes dealer and they wanted to charge me a whopping $1000. The part number i got from the dealer is A 906 850 01 68. They call it the rail / retaining to roof frame.

Maybe I heard wrong, but i've called them twice to confirm. Does anyone know another cheaper source? I've tried americanvan.com, but it required drilling. I want it to mount on my existing holes. Hopefully someone can help. Cheers!