Going to 18" rims questions

18x8 with a 4.5" backspace. I'm running a 235/40-18 on all four corners. I might be able to go down to 17's but I'm running Wilwood brakes so wheel sizes are limited. I bought the car with the wheels and they're starting to grown on me but I make a change down the road.

Nice ride! The front looks like it fits good. The rear looks a little small tire wise or is just how the pic makes it look?