I think guys who have not heard a rear mount are in for a suprise! When it spools up it sounds a little like a jet engine spooling up. Blow off valves or bypass valves are more critical on manual shift cars. You hear it when you snap the throttle shut when in boost. The location of the MAF sensor also has an effect of how this excess boost can be vented. You do not want to vent off air that has already been metered. Whether it is a blow off valve or a bypass valve that vents into the incoming air stream, I would leave it to Corky to figure out since he has to stand behind the kit.