I have a GT Haus / Meisterschaft / American Roar Racing exhaust for sale for a 6th Gen ZL1.
Had it on my ZL1 1LE for around 1,500km.
It is too loud for the noise limits at the track I go to so going back to stock.
Price is $2,500 USD. Located in Detroit, Michigan area or Windsor, Ontario.
https://gthaus.com/product/chevrolet-camaro-zl1-2017/