Thanks for the link. Hadn't seen that one yet.
As for the sound, my thoughts are, the exhausts on the Concept's are likely without cats, and probably have something similar to the SLP Loudmouth. Seeing as they spend most of their lives on the show circuit, they don't have a "production" set-up which a production model would require.
My guess is, the production model will be quieter.
I think the sound of the Concept's is something that the owners of the new Camaro will be able to replicate with an aftermarket system.