30 psi? You mean 30 ft-lbs?

Tell us the size of the bolt (diameter of the threaded portion) and we can give you a good idea of what the torque should be.

As for removal -- hard to counsel you. If you over torqued it and it broke without messing up the threads, then the remaining piece should come right out. If you stripped threads before it broke, then you're likely into a situation where you have to drill it out and, if you're lucky, re-tap. More than likely though, you'll have to drill a slightly larger hole and put a thread insert in. You'll need as much room for access as you can get if you have to do the latter.
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82 242-6.2L; '17 Mazda3; '16 Crosstrek