is it front of rear?
BMW rear shock mounts are prone to fail...if it squeeks its most likely bushings
popping sound can be anything from bearings to CV joints to drive shafts
try jacking up or pushing down all corners of the car to see if you are reproduce the sound...at least you can narrow down to a specific wheel
springs can "pop" but only if you overload them suddenly or if you have aftermarket springs that have progressive spring rate or if you have lowered/cut springs...they pop when the coils slap together very quickly