GMPartsGiant.com offers the wholesale prices for genuine 2016 Cadillac ATS Sedan parts. Parts like Antenna Cover are shipped directly from authorized GM dealers and backed by the manufacturer's warranty. Parts fit for the following vehicle options. Engine: 4 Cyl 2.0L, 4 Cyl 2.5L, 6 Cyl 3.6L. Model Code: 4 DOOR LUXURY SEDAN, 4 DOOR PERFORMANCE SEDAN, 4 DOOR PREMIUM SEDAN, 4 DOOR SEDAN.