1. You have to ask whomever you're purchasing from this.
2. I have GXP brakes F&R, they definitely are worth it for looks alone. I got all my braking components from ZZP, so I can't really help for "on the cheap", but why don't you check out some local junkyards?
A lot of GM big brakes are interchangeable between many models including Cadillacs to Corvettes.