the ECU tuner for my skyactiv 2.5l with mistu ECU (also VVT/"mivec") offers aftermarket cams. They require a different ECU tune and 93 (USA) gas. I don't get why these guys do all this work and use a piggyback, when the oem mirage ecu is fully tunable. I'm guessing the know how is missing, because they could get a much more complete tune otherwise.