I did mine a few months back.
I found the 4 bolts were jammed solid and rusty, the torx head just rounds off, but it is still very easy to remove the 4 bolts.
Cut the 4 bolt heads off with a small angle grinder ( that only takes 5 mins ), then lever off the old hub, that leaves about 20mm of studs to unscrew.
Using the angle grinder again make a flat on all 4 bolts. Unscrew the bolts using molegrips. Without the flat spots the molegrips will just slip round on the jammed bolts.
Its an easy job and they lasted 130000 miles for me.
I got my 2 rear hubs for my Mondeo Estate from ebay £35 each brand new, lots of outlets sell them and free delivery.