Heads Up! I bought my 2004 Cayenne S last April and been unhappy with its inability to accelerate out of a slowdown in traffic. I found that I could manually downshift and that would work but I wasn't happy with that compromise. Something was just not right! Bingo, this past week, the dealer said that there was a Service Bulletin to replace the coil packs for Cayennes with hesitation problems. Every single one was cracked and was replaced with the later model. That solve my problem. Having owned several Porsches over the years, I just knew Porsche engineers did not intend for the driver to have to manually downshift everytime the traffice slows down. I am now enjoying my Cayenne S like it was meant to be driven.
PS, tried Toyo Proxies (19inch) and had to resort back to Michelin Diamaris because Toyos too loud and hard on your brain when going over speed bumps. The softer Diamaris made for a nicer, quiter ride.