New 2003 ZTW owner

I have a 2002 SE wagon. Just purchased a 2003 ZTW 2.3 pzev engine. The 2003 has the larger 16" rims. The 2003 ride is harsh. Is there a difference in the suspension between the 2.3 ZTW and a standard wagon? Can I use the 15" rims on the ZTW for a smoother ride?
Congrats! Those are really hard to come by these days. The suspension is identical, you just get the cooler 2.3 Duratec motor which is way more reliable than the older Zetec. Yes you can downsize to 15" from any Ford Focus.