technically I beleive wheel offset relates to how it lines up with your susp. So its the distance from the center of the wheel to where your hub mounts to. So more positive offset will push the hub mounting face out more towards the outside of the car. Using 17x9 as example, the 05 wheels would have 7 1/4 bs and 45mm of Positive offset, while a typical latemodel wheel only ~5.9bs and almost 1/2 the offset