Uhmm, just my opinion but I would not use silicone sealer cause it is an insulator, both electical and thermal.
If nothing else, you might try anti seize,cause it has copper metal, but I don't know if it will melt off. What you
want is the same as the heat sink paste on CPUs in computers. Heat conductive.
I am surprised the bmw kit does not come with it. Does anyone know of available source? Or any canadians want to ask your dealers what they use?