You'd think so, wouldn't you, but it's not true. The only part that can affect body roll is the anti-roll bar. The reason that more damping and stiffer springs provides better turn in is simply due to the increased stiffness in the front end, which of course then provides it's own problems on bumpy tracks. As with all aspects of suspension setup, it's about finding a balance that works for your style. If you haven't seen this, it's a flippin amazing article. I thought I was pretty hot at setting up chassis and suspension (for on road anyway), but I learned a lot from these articles.

http://users.pandora.be/elvo/c1/index.htm

The first chapter is tyres as per the link, then it moves onto suspension settings, the 'next page' button is at the bottom. It has a clear explanation (as long as you have a good grasp of mathematics) of every aspect of suspension setup. The aerodynamics section is also particularly interesting...