when i put the shaft assembley on my balancing machine they are always out of balanced
i only done 3 in 5 years which were ok

shaft can wear out of round off center ect which will change the mass

all so what about the wear on the shaft seal aear or the main core
a coupel of thou wear and it will still fill lose with a new bearing kit in there and still leak oil

what boost are you running bill ,is it standard you may get away with it being standard