I have decided on using a S-300 varient as my top turbo to replace the 35 but I have a few questions is the internal wastegate on the htb2 or cool twist turbos large enough for twins I think they have dual volute wastgates but I ain't sure, and how can I make the downpipe flange for the housing which uses a 4'' vclamp like used like all B1 turbos the reason I am confused is the downpipe off of me 35 is extremly heavy built and the pipe I bet is at least 1/4'' thick but there is no way a vclamp will clamp to turbine housing flange and then to a 1/4'' downpipe it is only made to clamp to thin exhaust pipe, or are what people just using regular exhaust pipe for the downpipe on b1/b2 twins. sorry for the long post but any help would be greatly apprciated

 

Yes the cool twist and htb2 should do very well in a twin setup. The internal wastegates for both
of these turbos are "dual volutes" and should be sufficient, however an external wastegate would probably be better.