The wheel size will probably be OK but the tire size 235/55 18 is quite a bit larger in circumference and I wouldn't recommend it, it will probably mess with your traction control, transmission (if DSG transmission) and definitely your speedometer and maybe other things too. I suggest to always try to stick with keeping the overall tire diameter as close to the same as stock. 225/45 18 is about 26" tall, a 235/55 18 is over 28" tall.
I'm not sure why you've chosen that size (235/55 18) but I'd advise against it,
Sorry for the late response, what did you finally get? I'm curious