[84porsche]

You can but it is a lot of work. Copper is not too expensive and you need to know how to solder. Best thing in my opinion is depending on the access you have, start with one room at a time and add the copper lines, hot and cold to every sink, its the bath tubs that are going to be difficult if they are fiberglass. If you have to repipe from the main, this is where it can be tricky tapping into the existing line. Have you gotten a couple of estimates. If you work on your car, this should not be too far off.