We used the Moroso 65042 stop to slow the Duster from 10.7's to 11.5's (no cage at the time). We had to put an extension on the stop to slow it down enough. It worked great aside from breaking the throttle cable in round one of the first elimination round because the stop stopped the gas pedal from making it all the way to the floor and broke the pedal end of the cable off. We fixed the issue by also putting a stop under the gas pedal. the car was very consistent and we went many bracket rounds with it that way. Now have a cage but still use the stop on occasion for index classes.