Well, I dunno exactly what it raises it, I haven't calculated it, but I don't like the idea of having a liquid that takes a while to burn off filling up the squishdish of my pistons. Call me paranoid, call me stupid.. I just do not like the concept. If I can figure out a way to better hit the sides, I'll certainly use it.
Just because they are out when its put in doesn't mean it disappears before the plugs are put back in.