I started off by putting four 64oz, four rod versions (Tim only sells two rod versions, I made the four rod versions myself) plus two 32oz four rod versions for a total of six. But with the new 5 plate design I only have two 64oz versions. I am going to add a third soon after I upgrade some of the wiring to handle the increase to 45amps. You could ramp up the rod versions with more baking soda to produce more but then it would get very hot. The plate design seems to produce a lot more but without generating as much heat. I also got my MAP sensor enhancer yesterday. So I will look to get that on the truck this week and see how it does.