I doubt you can go lower without changing the can. The best thing would be to get a non wastegated housing and use a external gate. They dont size them using A/R they use cm2. Like a 12 is the standard size on most 94-02 5.9s. some of the earlier dodges had a 18. Obviously the smaller the number the smaller the housing. You can find 14s and 16s also.you can find them between 50-100 bucks usually.