255 is THE WIDEST you can put on these cars. I have 255/50/16 Michelin Pilot XGT Z4 tires on my Intrepid. They only have a couple millimeteres of clearance, but they don't rub. Any wider would be a problem. I highly reccomend getting as much rubber as you can under these cars. They are amazing when you give them some serious tires...especially if you have the sport suspension. Using a Gtech, I pulled a continuous .94 G's after my tire upgrade. Tested and verified many times. I highly reccomend the XGT Z4s. I also have Pilot Sports on my Lincoln Mark VIII. Those tires are incredible in the rain, but have a little more sqirm. It feels like the sidewalls are softer, which isn't what I expected. But I think they are designed for extremely low profile situations where you need a lot of sidewall flex to compensate for the shortness of the sidewall.
Scott
Scott