Or even better, take the mbc off, and put a factory bpv on the car will run 100 times better. Then get that Cobb ap you were asking about. What is the exhaust you have on there. Is it a catback or turbo back? The stock bcs works just fine. As stated above randy has one. There is no need to have that thing at this point. The ecu adjusts boost based on several things, so when you have that on there you are only causing problems for the ecu, probably the issue you are having. Either tune for it(not a nessesary part for your mod list) or take it off. Not trying to be an a$$ hat, just wanna help you out.
Cobb ap stage 2 ots, catless uppipe, catless turboback, Cobb Sf intake.