And this is why a GOOD Turbo kit cost more , those looking at turbo kits need to keep this in mind
" There are also two main types of wastegates, internal & external. Both are there to perform the same task, the only difference is location and effectiveness. Internal wastegates are located inside the turbine housing itself, and although effective at re-routing exhaust gasses around the turbine wheel, they can impart a good bit of turbulence to the exhaust flow path. This increases exhaust system pressure and hurts performance. The external wastegate, the true performance choice, has provisions made for it’s mounting before the turbo on the exhaust manifold. An entirely alternate flow path is created where exhaust gasses skip going through the turbine housing altogether, contributing much less to turbulence in the system. They also tend to be more accurate at controlling exhaust flow and turbo boost; combine these two attributes and you have a recipe for superior performance. "
Internal waste gates cause poor flow right at the point where the Exh gasses need to flow the best and thats at the turn down out of the turbo this hinders a good spool up and causes lag at all RPM as well as causes poor flow at higher RPM BUT it helps to make cheap kits