not sure if this helps, but i ran endless bbk (6/4, 345mm/325mm*i think) and project mu bbk (6/4, 355mm/345mm) on my 350 and the project mu kit was: lighter (cuz the rotors weren't as thick), more responsive, and cheaper.
i'm running the pmu kit i had on my 350, on the 370 ...thanks to a pmu conversion kit