I'm not sure what phunkdokta meant by that, but I hope this doesn't degenerate into a name calling match.

As for a blow off valve, you hit the nail on the head with your description of the blow through system. Please don't use a blow off valve on a draw through though! It will vent the pressure yes, but that pressurized air will also contain fuel! Imagine the sound then, "ssssssrrrrrreeeeeet, piiiiiiiisssssssshhh, KABOOM!"