First time I took mine off it was a PITA. Lots of PB blaster and then ended up getting a big ass rubber mallet from Home Depot. Once I finally got them off. I used a wire brush to clean up al lthe rust on the hub, back of wheel, and rotor. Hit it with some brake cleaner to wipe it all down and used anti-seize. Now they pop off so easy. Just be sure to grease the back of the pads or you may squeal.
FYI, my DBA rotors actually have threaded spots on the rotor hat to help pop it off. It works really good. I don't know the size or threading of it off hand though.
2003 Corvette Z06 - MGW shifter, Corsa X pipe, Corsa Xtreme exhaust, Texas Speed long tubes w/o cats, PowerStop rotors/pads, Conti DWS tires, C6Z51 F&R sways, C5R headlights, tuned
04 GTO - sold