18 by 9.5, ET 45 is never going to be deep concave. Concavity isn't an option box on a build sheet, it's the leftover room between your mounting pad and your outer lip. Offset sets the outer wall, your caliper sets the inner one, and a spacer moves the wheel without changing either. On a three piece it's the same equation twice: pad depth plus lip width equals your offset AND your face. Stock brakes for the fitment, or big brakes and a flat face? #ThreePieceUS #cars #wheels #concavewheels #wheelfitment #offset #threepiecewheels #bigbrakekit #stance #wheelspacers