Great purchase! Will they fit on the front without the spacer? Can you measure the distance between the strut tube and the tire/wheel where it would come in contact please? Also could you hold up a straight edge to the fender lip on the front and measure in to the point of contact on the tire/wheel please?
I guess these 18's clear the front caliper easily. Do they without the spacer? I agree with your choice of 18x9.0. Do you feel the 265's are a little to big for a 9.0" rim? Did you ever put the rear wheel/tire combo on the front and see how much clearance there was as listed above with the 9.5 ET23?
Good luck and thanks for being the first one to post a square set up for the track.