I think it depends on the wastegate you use. I'm not 100% sure on this, but I think a boost control system is used to INCREASE the boost that you can make with a limited wastegate...meaning it allows you to run more than a wastegate alone would allow you to run. I know with the boost control system disconnected on our cars (running WG alone) it will only make 10-12 psi. If you have a wastegate that opens at 15psi, and you want to run 15psi, I do not think you would need a boost controller.