I don't know yet. It just became apparent yesterday when I realized that I can't boost above say.. 3-5psi, while the EBC is set on 10 psi. I don't believe it is safety boost because I'm pulling a code 55, and it seems to run the same no matter what now. Oh and, I hear a hissing from the driver's side of the engine bay when in boost. : \
I'm going to try and diagnose more today and hopefully find the leak.