I think my best bet at this point would be to take it to a tuner, and see what their recommendation is. Do you think if I got a quality exhaust with a cat, and a quality tune, that it would run reliably?Can't say what it is from outside pics. You either need confirmation from prev owner or remove it to look inside. Either way if it's throwing efficiency codes then it's not good enough.
16psi steady boost pressure but it spikes to 21-24psi at the start when you floor it.