Apparently when Porsche first manufactured the Cayenne it only came in a V6 model. When they kept getting reviews that the vehicle is underpowered they decided to start making Cayenne's with a 5.4L V8. And this is what the service manager at the dealership told me, they just dropped a new engine in the car without updating any of the other systems so the new larger engine was too powerful for the parts that were manufactured for the V6. Not only did they update any of the other components to withstand the power of the V8, they had the pipes made out of a "high grade" plastic. One night after I just took the vehicle home out of the shop for another repair (which I'll tell y'all about too) I was doing about 80 down the highway when I heard a loud bang and it sounded like a machine gun was going off under my car. Had to pull over and leave my car on the side of the highway overnight, apparently the cooling system overheated and the plastic tubes melted, burst, and sprayed coolant all over the engine bay of the car. I was then forced by Porsche to purchase an "upgrade" kit to convert the pipes to aluminum versus plastic. The dealer also informed me that this happens to EVERY SINGLE CAYENNE. So if you decide to purchase one please beware, make sure the tubes have been replaced already or you can look forward to a $3,000 repair. Currently there is a lawsuit going on between Porsche and some law firm and New York, so there is a possible reimbursement if you've ever had to pay out of pocket for this expense like I did.