This conversation is civil compared to my "Latest Z400 photos" post which morphed into an ecu battle and photographic critique. Thanks for all the fact information. On a non technical note, when I removed my stock pipe and Coffman the exhaust color was black and sooty. I always thought lean would be a light grey or tan. With the Musarri full system the exhaust color is still blackish. If the fuel mixture was to lean out, wouldn't the color be lighter?