Like the first reply said this has been beaten to death, yet as far as I can see no one has yet posted a key fact (and there several misleading replies).

Correct - you don’t need a BR with an MSD. But if you want to (or do) run one anyway (as asked in this thread) it makes absolutely no difference. It will not affect your performance, cause a stumble, reduce power to the coil etc etc. The MSD uses the original coil feed purely as a trigger wire. All it needs is a signal and does not care about the voltage, and consumes effectively no power. It has its own power feed.