The patterns the same it's just that the tires aren't lined up directly, same tread patterns I just stacked'ed up up for the pix. That and the wider tires have bigger/wider tread blocks. I did some research and the PS 3's are actually Mich's "Green" tire or Eco friendly if you will just like conti's and Yoko's have. The PSS's are the new tech replacement for the Mich PS2's.
Below is a side by side 225/255 with the tread patterns lined up....