Probably this has come up a lot, but I'm not thinking anything drastic.

I don't put a lot of mileage on cars, but I'm guessing there is a 33% to 25% tread left on the Bridgestone Potenzas on my XF.

I'll just throw this out since it is what got me thinking about this today: i was working on a '58 Alfa Spider and removed one of the tires (165R15) and leaned it up against the XF's front wheel. I was really amazed as to how much taller this vintage wheel/tire was.

The wus part is I'd really like a bit more compliance in my tires when it comes to getting new ones. And I do like wheels to fill the wheel wells - as much as 'reasonable'.

These are baby steps, but I'm thinking 225/50R18 and 255/45R19's. I'm well aware of speedometer discrepancies, but with the right tire and size, will I feel a difference?

If these sizes start making the car squirrely, then I'm not interested.

Brand: someone bought Continentals for their XF and a few commented that that was a great choice. I don't remember the model of the tires.

While I want tires which will deal with rain (infrequent in SoCal, but can get very nasty at times) my choice would be summer grand touring, only 'somewhat' aggressive.

A reasonable (not really possible with these sizes) costs, but certainly not just, 'good 'nuff'.

If you are into more 'extreme' tires, that's nice, but not remotely what I'm looking for. Any suggestions, please keep in mind the Wus Factor.

Biba