That's what I've also heard from the guy with the 2 F6's. We'll know soon enough as one of his cars is on its way to Nizpro shortly. I'm also very happy with mine. After fist f*cks destroyed the original engine, I had a new one built by Dynowog. It is very quiet from cold start, and you cannot pick it from a stock pistoned unit after about a minute of running. LOVE IT. Back on topic though, usually the loud pop is due to the spark being blown out by the extra boost. The 10PSi tune should never be run WITHOUT regapping the plugs. Sometimes, however, the problem can be more serious. I really hope it's not a rod.