There is a simple trick to the brake booster swap. Slide the driver's seat all the way back, then prop the driver's side door open. You sit on the ground between the door and the body. Use a 3/8" drive 12" extension and a universal joint socket. You may need one of those weird semi deep Snap-On universal joint sockets the get the right clearance between the end of the bolt and the socket. You can get to all the nuts with a minimum amount of difficulty. Some tape or a disk magnet stuck in the socket helps hold the nuts to get it bolted back in place.
Same here... it is really difficult to get the broken bolt stubs out without damaging something else.
I have the fix for that, and it is inexpensive and lasts a very long time. The cost is: about $19 one side, $26 for both sides.