Car makers change vendors all the time. Part quality, price, ability to deliver quantity, etc. The dealer I work at buys genuine Volvo parts for warranty repairs, but also offers aftermarket parts for a lower price. Example, genuine front rotors, $110.00, Brembo front rotor, $79.95. Genuine water pump, $120.00 while they stock an aftermarket for $40 less. One thing to keep in mind, if the part is represented as "genuine", it carries the 1 year unlimmeted mile warranty. Aftermarket parts range from 30 days to as long as you own your car. It pays to shop around and ask about warranty. I just bought a starter for my 240. Employee price was $102.00 at the dealer. Aftermarket lifetime warranty Autolite unit was 69.00 retail. Guess which one I bought. I keep my cars on average 12 years.