I had the OEM stock 20inch GTR rims

Hey I'm new to this forum and I came across your yellow z beautiful btw. I have a question I was thinking about purchasing a set of replica GTR rims 18x8.5 and 18x9.5 idk if you have originals or not, but is that the same size you have? And also what is the exact tire size you have on both front and back? I was also wanting to lower my z how far is yours lowered and is there any rubbing issues? Thanks