GMPartsGiant.com offers the wholesale prices for genuine 2012 Cadillac CTS Coupe parts. Parts like Communication System "Onstar" are shipped directly from authorized GM dealers and backed by the manufacturer's warranty. Parts fit for the following vehicle options. Engine: 6 Cyl 3.0L, 6 Cyl 3.6L, 8 Cyl 6.2L. Model Code: 2 DOOR COUPE, V 2 DOOR COUPE.