I agree about the process, I can't tell you how many "I seafoamed my car" threads I've read, only to read that they did it wrong.

And sometimes it's best if you let the vac line take so much that it kills the engine, but killing it manually when it's all gone is good too. The smoke is produced from putting it in the vac line only, if you were to just put it in oil and/or gas, it wouldn't smoke.