What does it look like to a college if I receive a P on my transcript compared to a C- in an AP course?
A P definitely looks better than a C-, since it could represent performance anywhere from C- up to A+.
Though getting a B- will look better than a P since you could have gotten anywhere from a D- to an A+…
Maybe, maybe not…
The B- will most likely drag down the unweighted GPA (and perhaps the weighted GPA as well), while the P might just be ignored.
The OP said AP class so yeah it will drop your UW GPA but shouldn’t drop your W GPA too much. A B in an AP course is still good.
I suspect that some colleges may not accept courses graded on a pass/fail basis. Check the academic requirements for the places you’re applying - and thinking of applying - before you make the decision to go for a P or a C-level grade.