Did you get the instructions with it?
I have two external wastegates and I have had an MSBC for years. It works, what I once thought to be very well. But I'll get an initial 2, sometimes even close to 3 psi spike before it quickly recovers and holds mostly within 1 psi stable for the rest of the run. But now I believe some of the newer devices are better these days.
I thought I remembered the instructions having a section on installing it with a stock style wastegate actuator as well. But I agree with Paul (pacecarta) and strongly recommend using external.