Just a heads up....
With running the gate behind the O2, double check but last time i was searching using this style from Punishment, using a tial F38 they wit where the radiator sits.
http://www.punishment-racing.com/mild-steel-38mm-recirculated-o2-housing-for-eclipse-talon/
To me it looks like the v band style like this would fit, i did email punishment and they haven’t tried it on a vr4 yet. This was like a month ago I emailed them.
http://www.punishment-racing.com/tial-mvs-38mm-wastegate-recirculated-o2-housing-package-for-eclipse-talon/
They can make the external venting type after the gate, to fit a vr4 however. You need to tell them before the order.
http://www.punishment-racing.com/stainless-steel-38mm-atmosphere-dumped-o2-housing-for-eclipse-talon/