To give you an idea about widths and offsets, here's mine. 9.5" and 10.5", ET25 all round. If you went 8.5" / 9.5", you'd have the outside of the wheels half an inch further in than this, then adjust for different offset. I'm lowered on Tein S, which is -17mm / -14mm front / rear. Oh, and mine are 19" so would look different if you're going for 18s, but you get the idea