I believe most use Permatex Ultra Black RTV ... I personally have some trouble applying the RTV (or any sealant) in a smooth manner ... I looked for other options and found none ... i did find the O-Ring cord and am giving it a try ... it is easy for me to apply and has held torque and sealed the breather covers thru my testing so far ... NeedsWings is a good place to get things we need for our Crossfires, and a good source of information ...
I'm not saying not to use the Mercedes sealant ... but I am sure most people use the Ultra Black RTV, and I am trying another option using the O-Ring cord ... whatever you use is your choice and your responsibility