Disc brakes still not stopping good

Think I found the culprit. 4 Piston SSBC calipers barely moving out with brakes applied. Took the brake pads out. (They were pressed snugly against the rotor). Pushed the pedal and only 1 piston moved. Blocked that one and the others barely moved. I have 1400 PSI,( I finally got a gauge on it), when I push hard on the pedal. Should be ok from what Im reading. Took the calipers off and its very hard to pull the pistons out. Not sure why. The o rings are flexible, No rust, but the piston is a little sloppy in the bore with ought the o ring. Maybe they are cocking in the bore? IDK. But i think this is the problem. Any thoughts? Thinking to ditch them and go all wilwood.