Looks good. Also the reason you got 10.5 on measuring it is most likely because the wheel width is measured from the insides of the each of the walls where the tire bead sits not the top/outside of the wall
Heres all the info
Wheels are black saleen replicas 18x9 24mm offset front, 18 x10 45mm offset rear.
Tires are 255/45/18 nitto nt555 front, 315/35/18 Toyo Proxes TQ rear.
I tested them out on the street and they hook nicely. The real test will be at the track.
Question... where are you finding these sizes. I just looked on Tire Rack and Discount and only find the Nitto DR in the 305/40 and nothing on a 315/35
Shock.. I've always liked your car... looks even hotter now... good show!
Do a search for the Toyo Proxes TQ. I think its the only tire that comes in that size.
Only a few tire dealers carry them.. I forgot the name of the place where I ordered mine. I have all the info and paperwork at work.