Fordguru, I thought the same thing about high roll centers on a low grip track that I used to run on with my SC10, but increasing grip by running a high roll center contradicts most of hte info out there. Like you mentioned, I think Fred alluded to it somewhere near the beginning of this thread in stating something like both setups will slide on low grip, but the high roll center will provide more grip. I had actually made a recessed u-brace for the rear for that track to get the roll center as high as I possibly could. That track closed, and last summer I ran on a higher grip (likely considered medium-high, I think), and kept gravitating towards the high roll center with bad results (twitchiness and snap oversteer on corner exit).

Personally, I don't think low roll centers used in high grip conditions only offer an illusion of better cornering power. The weight transfer to the outside tires (once the chassis stops rolling.....key point) can't be overlooked, as it does increase overall traction I believe. The difference between low grip and high or even medium grip surfaces, though, is that on the low grip surface you can't even generate enough g-force to get the chassis to lean and transfer weight.

My two cents. Comments????

Can't offer anything on the center diff bit, as I don't run 4wd.