Whiteline Adjustable swaybar, 20mm (road), I paid $175 for mine (22mm for track)
You can also buy an adjustable one for the rear. I think the options are 24 and 26mm, need to check. The catalogue will class the two options as "Street" and "Race". If you are running a LSD or a Quaife Diff I would use the larger of the two for the rear.
If you were wanting second hand , I found that an 18mm K-MAC front bar, and a 16mm rear bar worked well, both of these you tend to find at swap meets etc.
If you are thinking why the diffence in sizes between whiteline/K-MAC, they have different mounting points, therefore they "work" the bar differently.:thumb