In 1986-92, GM-Canada had a very successful series for IROCs/TAs-only. A fellow named Ron Fellows graduated from that series. And the 1LE was a DIRECT descendant of it, as well.
This car may be so good that GM may have to consider something like that, again. Viper Cup, Porsche Cup. Successful series for single-marque cars. And a way to get them on-track without the hassles of reconfiguring the car to satisfy Ford/Mopar/Import "playpen rules". And a way to sell some parts, too.