InfinitiPartsDeal.com offers the wholesale prices for genuine 2013 Infiniti M56 parts. Parts like Rear Seat Belt are shipped directly from authorized Infiniti dealers and backed by the manufacturer's warranty. Parts fit for the following vehicle options. Engine: 6 Cyl 3.7L, 8 Cyl 5.6L. Trim: Base, Premitec, Premium, Premium Touring Tech, SportPre, SportTec.