GMPartsGiant.com offers the wholesale prices for genuine 2018 GMC Terrain AWD parts. Parts like Heat Shields/Exhaust are shipped directly from authorized GM dealers and backed by the manufacturer's warranty. Parts fit for the following vehicle options. Engine: 4 Cyl 1.5L, 4 Cyl 1.6L Diesel, 4 Cyl 2.0L. Model Code: 4 DOOR SLE2, 4 DOOR SLT1, 4 DOOR SLT2.