GMPartsGiant.com offers the wholesale prices for genuine 2021 Cadillac XT6 AWD parts. Parts like Sunroof are shipped directly from authorized GM dealers and backed by the manufacturer's warranty. Parts fit for the following vehicle options. Engine: 6 Cyl 3.6L. Model Code: LUXURY X-OVER 4DOOR(GMNA), SPORT X-OVER 4DOOR(GMNA).