For big turbos that use big external wastegates on their turbine housing. This means more stable boost control, especially for big turbos and high boost. We used the Turbosmart Hypergate 45mm wastegate (not included) which would attach to this 3" stainless steel divorced flow downpipe. Other 45mm V-band wastegates may work but we've not tested other models with this downpipe.
Popular turbos that have the option for an external wastegate that can be used with our manifold/outlet/downpipe combo are:
Our favorite is the GT3071 for good spool response and ultimate power potential.
This downpipe is a 3" unit that uses a different flange than stock. You will either have to use our 3" exhaust system or build your own. If you're running on the track and don't have to worry about noise restrictions, a simple dump tube would work.