[McBill]

Are you still losing pressure via the leak tester that you built? Spray down all the hoses and joints with soapy water while using the tester on the charge side of the intake track. Finally, check the metal tabs holding the core of the intercooler to the plastic sides of the intercooler. Those are known to pop loose causing the intercooler to split apart between the metal and plastic.

Also, that Mishimoto intake should technically be tuned for.

 

[McBill]

There isn't much that can leak that you can't get to. Any work done recently to the intake manifold? Check for a tear in the intake boot at the turbo.

 

[McBill]

Maybe. What gauge are you using to monitor boost? Do you have a way to monitor A/F Corrections?