I'm unaware of any 13" diameter Tuff wheels... I've seen the 15s and a cpl 14s... no 13s.
What ever you choose, determine if the feel of the wheel is ok... my experience has found that the OE Tuff wheel (15") is much too slippery (and too large in diameter).. can't grab it for decent performance handling. Get one that has a thicker grasp... leather preferred. You'll appreciate the difference.