Adaptive PCM at work. Try taking off the battery for a few minutes to reset the PCM. Then take it out and drive the snot out of it. Adaptive PCM will re-learn your "new" driving style and adjust fueling maps and spark advance timing for more "performance" vs "street" driving, within a bound of engine safety mind you (as per DCX engineering and software writers permit). Exhaust gas temps and air fuel ratio monitoring would show a difference if you had either measurement device hooked in.