So how big is your downpipe now? When we cut mine we welded it to the non cast section so it's only like 2.25" on mine...
You grind it down and weld at the cast looking section of the belmouth?
I have an AVO 15psi wastegate actuator too but mine spikes and the boost is inconsistent - not overly happy with it really. We'll see with it turned down so it only spikes to 15psi and better boost control.