I have the Roush Racing rear swaybar on my Cougar, and I like it. Got it for a great deal to ($73 shipped brand new, in the never-been-opened box from Roush). Check out www.readyparts.com to find them.
Note: He's a great guy to deal with, but is sometimes a little slow at answering emails (PM me to get his new email, the email address listed on the website forwards his mail to this address, but he said he has trouble with not getting all his messages sometimes). Plus, his site hasn't been updated in years, so things like the order tracking do not work. The plus side is that you pay through Paypal, and he sends you the UPS tracking number on their. I believe that ReadyParts Inc. is not his 9-5 job, but an "on-the-side" business.
Nathan
Keep your front bar. Get the roush bar. But really they're not gonna have much affect on body roll but more on how it behaves. Like bigger rear bar will help get rid of the understeer that is common with fwd cars. There is something autox phil posted about front bar and all that you should maybe read it.
The Roush bar is 21mm, compared to 19mm for the stock bar (I have a Cougar, which has the same size rear as the CSVT). I don't know the size of the stock regular Contour bar.
Nathan