I blew a head gasket after I dynoed the car yesterday because my direct scan was causing a backfire at WOT. When the gasket blew it pressurized the cooling system and blew the thermostat neck out, it also took the threads out of the intake manifold. Luckily I was almost home. I found some references to an EMI shield that might cure the backfiring. Does this really work? I won’t try DS again until I'm sure the problem is corrected. It’s too hard on the engine to just hook it up and see what happens. If it does work, where can I get it locally? I'm tired of dealing with vendors and mail order because something always gets screwed up. Thanks for any help or information you can give.