The question really we should be asking is does a diffuser have any noticeable positive effects on an 1/8 circuit car ? Its something that perhaps we wont know until people buy the kit and start doing back to back tests with the part fitted and then taken off. If it is an improvement and proved legal then for sure it will start appearing on other makes, If its just a gimmick that achieves little in real world then I guess most will be running without it anyway. Its like carbon inner wheel discs that have appeared on other makes which also supposedly are an aerodynamic aid ? but I cant tell any difference in performance with or without them ? .