Not to downplay the
Not to downplay the awesomeness of the Camaro at all, but the Z/28 is a dedicated track car where the M4 certainly is not. The M4 is a fast luxury car where the Z/28 dispenses with even such "luxuries" as air conditioning and a radio. They are apples and oranges.
The Z/28 is a brilliant car but daily driving it would be insane in most areas. The M4 is daily drivable pretty much anywhere any performance car is feasible.