Breakup/misfire under boost is almost always spark related. What else could it be if you're looking at 11.5AFRs. Of course the AFR's shoot up when you're misfiring. The Oxygen sensor is reading more oxygen because you're not combusting it. Check you spark plugs and gap, then make sure your coilpacks aren't taking a dump.

How big are the corrections you're running on the SAFC? You know that RS Enthalpy is located just on the other side of the Bay. If your tune is so bad why don't you tell us what's wrong and we'll fix it. For free. On a dyno. So why do you hate the Enthalpy tune?