Remember wet wall framing requires a 2x6 footer and top plate ... to leave room for drain pipes and other plumbing. If you use 2x4, you will discover it is too narrow. If the plumbing is on an outside wall, remember to compensate for the possibility of freezing pipes.
Finally, think through your electrical needs while the walls are open. Easier to run new electrical with studs open.
Here is a good intro video
And a pic of one setup (although I use copper, not PVC)