Th previous gen perf exhaust was $1299 and cross bars $199. 2021 Crossbars $499 and Perf Exhaust $2149. Seems like some serious price gouging on 2021 accessories.
In regards to the exhaust I don’t think you’re comparing apples to apples really...
From the link you posted it looks like there are (2) exhaust options. The $2149 option is for a dual rear exiting system, while the single side exiting option is $1649. The $1649 side exiting option would be more comparable to the GM performance exhaust option offered for the K2’s. And the obvious better choice based on the performance increase numbers.
In better news in regards to the GM/Brembo factory brake upgrade it looks like they will be offering a matching rear brake upgrade as well. It says: “Similarly tricked out rear units also are available and both squeeze larger Duralife rotors.” Fronts = $2,895
Rears = $575
Even if the rears are a 4 piston caliper with larger diameter rotors that’s a decent brake upgrade for <$3,500.