I'm gonna go out on a limb here. I'd guess that Mitsubishi found or developed a cheaper setup that is similar to the Bilsteins in the MR - perhaps not as good as the Bilsteins, but softer and more responsive than the older setup.

I remember feeling the bumps and undulations in my stomach when I test drove the VIII for the first time. The 2006 IXs & RSs are definately softer. Think of a slightly stiffer MR, ever so slight, and you'll understand better what I'm talking about.

Anyone else agree with me?