The rear of the Focus has a problem with body roll, especially the sedan and wagon. Go figure. I have been told that front and rear anti roll bars are actually over kill for the everyday driver. At the price of this bar, I had to ask since I could do it and then my suspension would be done.
BTW, dwdgsi03, I know exactly what you are saying since I have BAT/Spax 50mm Springs and Damps, Poly Boshings, and the FS front strut bar. It did diminish it quite a bit. This could only make it better.