I just replaced the same thing on my Cavalier. I guess I was lucky the bolts came right out. Does your take a T-55 Torx? Did you have a decent bit before it got chewed up? I guess the extra salt and corrosion 300 miles north make a difference.
I remember trying to put front brakes on my Sister-in-laws Oldsmobile once. The rotors were scored so I had to take off the brackets that hold the calipers to get them off. One side came right off. The other side destroyed every tool I could throw at it. I finally borrowed a Snap On T-60 from a friend that worked a a GM dealer. He gave me the hint to apply heat. So I tried it and it worked! Come to find out, one side had red Loctite and the other didn't. The red Loctite (cannot remember the number) is supposed to be heated to 500 degrees before unscrewing. I wonder if your bearing hub didn't have some of that shit on it.