So I got more information for you Al. The 18s and 19s are not a match. Becuase the center get compressed on the 18s, the wheels do not look close enough to the same as one another to put on the same car. The 19s and 20s are a match, but the 18s do not match the 19s or 20s.
So 19s and 19s are pretty much the best bet.