ALL Stoptech BBKs are balanced. That's what Stoptech's business model focus is on. Balanced brakes where you don't have too much bias on either the front or rear. Stoptech sizes the piston sizes and amount of pistons based on the vehicle's stock system.
Yes and no. If you get them as a kit meant for your vehicle, then yes they are. But if you randomly grab at whatever caliper / rotors that they have off the shelf, then no, they're not. They have several rotor sizes and several caliper sizes. But even for the same calipers, they have different piston sizing arrangements that can be setup to meet different vehicle requirements. So though two sets of calipers meant for two different vehicles may look the same, the internals may be sized differently.
Additionally, another consideration is the master cylinder. Any vehicle's stock master cylinder only holds so much fluid and can deliver so much full volume. If you get calipers with pistons that are way oversized for the your application, you'll find youself bottoming out the brake pedal without maxing the calipers.
So make sure whatever you get from Stoptech is actually tailored to work with your vehicle. If in doubt, call them.