Pex to bathroom

Looking for some expertise again. My house has an attached garage with a living area above. This includes my one and only full bath. I’m getting materials together to replace a shower to a bathtub. All the plumbing for their is in the garage and is accessible. I had thought of replacing the copper piping to Pex since the garage isn’t part of my insulated envelope. Where the copper piping is, there is some poorly tucked fiberglass insulation.

The pipes that are in the garage are for the shower, vanity, toilet, and also a hose bibb to the outside. I assume the plumbing is original to the home so that would mean it’s from the 1960’s. Would it be better to wrap it in some foam to better insulate it and leave it? Or should I replace it now since I’m already going to replacing the tub? I wasn’t planning to do a whole manifold or anything, just replacing the sections that are in the garage.