[88turboii]

i had that same problem with teh BNR stage 3, you can try running an extra spring from the WG actuator to the flapper to help keep it closed. I dont think the cat is causing it to open though, stock turbine is just really restrictive

you should be fine with the stock tmic, ive never seen it get above 150F on the street, and thats running 15 psi on a p-trim hybrid