rear ceramic pads
Powerstop Evolution Ceramic (same brand as front)
More Information for POWER STOP 161352
More Information for POWER STOP 171352
More Information for RAYBESTOS ATD1352C
More Information for RAYBESTOS PGD1352C
More Information for CENTRIC 10513520
Further comments (this is just me talking):
GM works very hard to come up with a pad package for every vehicle that meets all required performance parameters. The use of alternate pads, all which have claims about their performance or other superior characteristics, have not typically been validated or vetted by the vehicle manufacturer.
Generally aftermarket pads will cost less until the really high-performance pads (ie. racing formulations) are considered. GM "production" pads are more expensive, and in many cases the cost is partially a reflection of whether some hardware may be included, which is not always the case with aftermarket pad packaging. Other factors regarding the cost difference(s) include the production volume of the vehicle, thus the specific pad(s) used are impacted by how many pieces a supplier is going to make to satisfy the production run and replacement stock of that part by specific PN--fewer cars produced, higher cost per brake pad set for the low-production SS.
Aftermarket sources can generally offer pads that fit for less because in many cases there is commonality on another vehicle that uses the same caliper or at least the same pad as identified by FMSI (Friction Materials Standards Institute), even if the various OEM's have specific friction specs for their versions, the aftermarket will make a more generic friction formulation and put it in their catalog(s) as fitting several different vehicles which happen to use a common caliper family--this is becoming very common with the Brembo calipers that so many OEM's are now using.
FWIW, here's the GM front production pad PN for the SS Brembo brakes:
92291022 - List price is $308.77, dealer cost is $186.56
What gets me riled is that so many owners (I'm not pointing fingers, just making an observation) shop brake pads, rotors, and other brake & undercar parts by price rather than quality or whether the parts are at least equivalent to OE or better.
In the case of the SS, a $45K car (my first home in 1975 was $41K by way of comparison) that can run 150MPH+ and weighs about 3900#, I would want to be SURE that I'm using the best possible components in the brake system--even if they create some nuisance noises or make more dust than I'd like.....but that's just me.