BTW - I run the same tire size (Pole Position s-04 255/40/17s) on 57xtremes (17x9 40 offset - no spacers). Here is how the same size tire looks when tweaked...
I think 18's fill that well out a little better but I love the handling (and cheaper rubber) on the 17 setup.
I am going to run Hankook RS3s this summer and move to a Michelin PSS for the wet winter.