I posted this in a different thread, but here again:
You don't want to run the Seafoam through the brake booster line not only because of the possible supercharger rotor coating issue, but any carbon that's developed on the rotors taking up space (carbon is what the Seafoam is supposed to be removing right). Removing either from the supercharger will result in lost efficiency. Like dsmuts said, run it through the vacuum T under the nose of the supercharger. Here is some links I found:
Grand Prixs Of North America • View topic - Seafoam writeup
This has been asked a few times lately so hate to say it, but might need another sticky or at least something in the writeup section. I didn't find anything there doing a search.