Forgive me for not knowing as I am new to the SHO scene. Coming from a Nissan Juke Nismo RS. This is a whole different beast.
Question. Can you use a MBC with this motor?
If so and you want to stop Boost spiking. We solved this with a MBC. Last year while Dynoing. My Boost solenoid failed completely. During a pull mind you. Lets just say my tuner caught the over boost in time. 26psi(and it was still climbing) when he shut her down. So. We sourced another Solenoid at the Nissan dealer($60) and to prevent this from happening again. He plumbed a MBC in the boost circuit to act as a relief valve. The solenoid still controls the boost but the MBC is adjusted so it cannot go over a certain adjusted PSI. Set the Boost to 20psi and MBC to just a little over that and no more boost spikes. It works awesome.
I dont know if this idea can be used in this situation since there are two turbos etc. Its above my understanding of this engine at this point.