Boost controllers are for turbo applications, it controls and can be adjusted to limit the amount of boost the wastegate is actually seeing, therefore allowing you to run more boost before the wastegate opens because the wastegates open under certain psi depending on the spring.
I have a few autometer guages and an aeroforce, but i may try a couple of these guages:
Tinted 7 Color 30 PSI Boost / Vacuum Gauge