Yes.. There are people out here running 19's.. maybe even a couple with some 20's.
Porsche only "certified" use of 16-18"s for your year car due to the increased stress on the chassis that 19's transmit. Porsche did substantial revisions to the 987/997 chassis to handle 19"s as a factory wheel.
That said, no one says you can't put 19s on your car. However, should you begin to crack or stress chassis/subframe pieces, don't expect Porsche to replce them for free
Comes down to vehicle use in part. Also, tire availability can be an issue. Not sure Pep boys carries a lot of high performance 19" tires
