Whiteline also provide narrowed anti roll bars although they are special order.
http://whiteline.com.au/
See 'Loose the lean' in the Tech section.
My beam is narrowed by 2 1/2" and this roll bar firms up the front quite significantly, it's lowered a little and I'm currently running Red Koni's but as it is a little too firm, I'm going to try gas Spax. (when I can get the different lenghts from them between the G616 and G492)