External wastegates are better for high performance applications (300+ HP) because they control boost more accurately at high flow/ PSI levels. This is at least the 2nd time I've said this in the past two weeks. PAY ATTENTION, PEOPLE!
Routing a dump tube... if you can get away with it, run it all the way back to the back of the car. Venting it anywhere in front of the B pillar is absofuckinglutly retarded for several reasons- 1) highly illegal, 2) highly deadly, 3) highly loud which brings us back to #1, and 4) half assed. If you're going to join it with the downpipe, make sure that the junction is at least 18" downstream of the turbine wheel.