I just purchased my 08 MKX w/ the 18" chrome rims and would be willing to do a swap for your 20's. I am in central Cal, Bakersfield, CA and they only have 200 miles and counting on the tires.
Just purchased last week and glad i found this site for accessories and mods. I Am happily pleased w/ the 08 and the Sync works pretty well. The 08 is White Chocolate TriCoat w/ light camel interior w/ dark burlwood accents. the MKX joins the 02 BMW 745Li and the 02 Lincoln Navigator in the family.