I heard that few days after you put sea form in your engine, you need to change your spark plugs and engine oil.
I pour 1 bottle into my gas tank and drove it. I can't really tell the difference but just feels better...
There is a video on e46fanatics.com. A guy let his e36 engine suck 1 bottle of sea form then his car produced lots of white smoke + bunch of error codes but I heard that is normal.