Here in Europe, the CSC exhaust is pretty common in the non-cat, mild-steel version.
On these, the design seems to have varied over time. Some of them are loud, some of them aren't loud at all. Some have a bigass exhaust tip, some more like stock.
A couple of people have had problems with cracks, I think where the mount is attached to the muffler, but this can easily be welded up.
I think the fit was mostly good.
Overall, not a bad system.
One guy recently bought the version with quad pipes and it was unbearably loud with a nasty drone.
The stainsless steel version with integrated cat was first available with the exhaust pipe on the left and combined with a controller and an air valve to add lambda control to carbed Xs. This saved taxes in Germany.
I have never heard of this version being loud.
So one could assume that the version above (for FI cars with integrated cat, exhaust tip on the right) would also not be loud. But who knows.
I don't think anyone on the german forum is using this version, otherwise I could ask.