The original OE radiator from Porsche is a plastic tank radiator with a single row aluminum core design. While this is generally accepted as good quality and durable, it just isn't enough for the Cayenne. The 955/957 is notorious for having cooling issues. Just driving down the road on a hot day can overheat the engine and off-roading and towing/hauling is much harder on the cooling system. On top of that, these SUVs are 15-20 years old now. Those still running the original radiator have definitely lost some cooling efficiency due to bend/damaged fins and tube clogging. Needless to say, CSF had a lot of issues to address while designing this new radiator.