GMPartsGiant.com offers the wholesale prices for genuine 2016 Cadillac ATS Coupe parts. Parts like Fuel Injector Rail 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: 2 DOOR COUPE, 2 DOOR LUXURY COUPE, 2 DOOR PERFORMANCE COUPE, 3 DOOR PREMIUM COUPE.