[mr2guy]

So it seems that both turbos are not the same size so this could be a sequential or series style setup where the larger turbo comes on at a higher RPM while the smaller is used to build off idle torque. This could mean that the factory headers are utilized and then merged into a smaller manifold that can divert exhaust on demand to either turbo based upon RPM or pressure. I can't see one bank of cylinders feeding a small turbo and the opposite bank feeding a larger one.