By the way HDDP. If I'm correct, those are your racing wheels/tires. I love that look. But to be clear, this is an example of an 18/18 setup, and not the 18/19 as standard with the XF.

I went down to one of my chrysler dealers the other day, just to bs with the service manager, and specifically about doing 18/18 on a street version. He really had no substantial information for me on this since "we don't have enough of them on the road to get that kind quality feedback. I'm sure it would cause some issues and I wouldn't feel comfortable giving you a recommendation on doing this". That was fair and I said as much, so the question still lingers, is an 18/18 really advisable for the street, why or why not.
Finally, I'm with you HDDP. I know the 19's are cool to some, but I'm not a big fan of the "BIG WHEELS" trend, and I think DC should have put the same size all around.

RGvivace: the wheel is discussion just gets down to personal taste, so while I voice a different view, I completely accept your views and preference. Viva the aftermarket!