I'm looking forward to seeing this progress, its still a fun project.

You might want to get the tracking checked if it has done that to the original tyres save wearing out the yoko's as they are not the longest lasting tyres you can get.

17 inch tyres you should hopefully get something like a 330+mm disk underneath which will fill them out. Have a look at getting a spare upright and then look and see if you can get uprated calipers off the usual suspects, porsche, merc, some alfa's, evo's. Keep the costs down while you are able to fab up some (or if the bolt pattern is correct you might get lucky and find some bolt on's)