Expensive car, expensive exhaust. Plus, it's more than bends and flanges. You're paying for R&D, there's guys that spend hours tuning bend radius, muffler size/shape/placement/baffle design to produce those systems. And then, after all that, they only sell a handful of them because they're competing with every other exhaust manufacturer PLUS every consumer that would rather piece a custom system together.
Would I pay it, even on a CTS-V or the like? No. A simple muffler swap/delete and a high-flow (or no) cats would be fine with me.