I hope I didn't offend my e21 bros.
They're cool when done right but for someone new to BMWs or new to car restoration the early BMWs are not a good "trial by fire" project. A good "learner" BMW IMO is the E30 and now the e36 there's thousands out there and they can be had affordably. Check out some of the projects and DIYs here in forums and you'll see a pattern - research, budget & patience are the 3 major considerations for any succesful project. Keep in mind, a "driver" ride is tougher than a parked project.
If you can afford to get yourself a beater driver the $$$ invested in your project car will pay off in the long run