Alright... went with the Advan S4 tires. Got them installed saturday morning and have put about 200 miles on them so far.

I'm pretty sure they are a little louder than the OE Michelins that I had previously.

Handling doesn't feel as precise with the Advans as it did with the Michelins (the XF is very a precise handling car). I'm sort of holding back on that last comment though because I expect they will break in after a few hundred more miles.

Haven't hit any rain/wet roads yet.

I like the look too... I'll post some pictures in my gallery (if anyone cares).