I want to upgrade to f-body brakes and I was planning on buying the kit from ZZP. The problem is I noticed that this "complete" kit that ZZP offers only comes with 2 calipers. Is this kit a complete kit for only two wheels? Do I need to order TWO kits? Check it out here:

https://www.zzperformance.com/grand_prix/products1.php?id=591&catid=138

Yes that is a complete kit. The rears don't need to be upgraded and can't be upgraded do to the e-brake. This kit comes with two fbody calipers, brackets, rotors and brakes lines for all four brakes. I would suggest to get goodrich lines instead of zzp if you are planing on getting ss lines.

rears are the same size on f-bodies as they are on w-bodies.

I've been happy with my zzp SS lines, they were the perfect length, didn't need to do any bracket mods like some people to give it enough slack.

So if I order powerslot rotors with the kit will I receive two or four of them?

It's a front brake kit, but here's what your $249.99 buys you:

Base kit includes:
2 assembled PBR dual piston aluminum calipers

Caliper brackets

2 banjo bolts

4 Copper crush washers

Front rotors, front brake pads and front SS lines are optional at extra cost.

I got the longer zzp lines and they look like crap and I just put them on last year, and the sleeve over the ss is wearing off and the braid is showing through.