The OEM kits aren't terribly expensive and come with seals for both calipers per axle so you only need one rear kit and one front kit. It's even better if you can get your dealer to pricematch, to say Heuberger's online price. My local dealer does it.
Here's the part numbers and the online pricing to match.
Front:
226297CA000
Rear:
26697XA000
I don't have the slightest clue why the rears cost double the fronts :p
As far as aftermarket options, someone else would know better. They do tend to be pretty vague as far as quantity and they're hard to find compatibility for. I ordered a set for my old car on Amazon from Centric. Good quality seals, wrong dang size.