You can use your doors, all the mounting locations are there already. You just need everything on the power doors. plus wiring. As for what cars you can get them from. all 92-95 hatch/coupes. Sedans have different doors and internals.
But like everyone has said. research, research, research. Read each and every DIY you can find on google and forums.
Just a FYI, they DON'T all have the FULL start to finish details. I learned that when I did mine. It's not difficult just VERY time consuming. It took me 2 days to do it solo.