Are these the Z’s that just fit?
yes, they fit exactly like an oem z

Do I just need to desolder the old Z and solder this in?
that is correct

- Is this compatible with an oem controller?
yes

- Is it stronger than an oem rumble?
that depends - if you have a phob you can adjust the intensity to be stronger or weaker than an oem rumble. and the auto intensity is def noticeable. think old school phone notification.

How do these differ from rubber capped sticks?
well they don’t have a rubber cap