they DO NOT WORK and are not worth the box they come in. the "vortex" or w/e it creates slows air flow down on supercharged engines and the MAF sensor will adjust the fuel/air so you will not get ne better gas mileage. if you dont believe me go to any auto fourm that has ppl that know car and they will say dont buy!
http://www.regalgs.org/forum/viewtop...hlight=tornado