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You own one now, might as well read up on them. To answer your question its probably around 14psi without a fuel pump upgrade. Around 15psi+ you would hit fuel cut.

Wideband is a tuning tool just like the AFC, you'll need a fuel pump upgrade and maybe a rewire to be safe. Does this car have a T-25? I would worry about upgrading that first because they can't take too much boost.