RE: exaust diverter on my .91l
Do a web search for RTV + silicone + "high temp"
It is "room temperature vulcanizing' silicone glue/sealant. Fairly common.
Dow Corning, GE, Permatex and others make similar 1 part silicone sealant that is suitable for higher temperatures. They all come in tubes. Locally here, the material can be found at any automotive parts store.