Please see my ad for M Roadster Z4 Style 224 M wheels. Square or staggered, either 4x 18x9, or 2x 18x9 + 2z 18x8.
On the Z4, they 18x9 fit fine in front with 245/45 tires that are both taller and wider than the stock 225/45 size, as the pictures show.
http://sfbay.craigslist.org/pen/wto/5337954703.html