Pain Train,
I don't think the parts on that Summit Racing page are what you want. That looked like just the rack & pinion gear from the rear. What you want to investigate changing or replacing is the limited slip clutches/discs whatever.
Maybe something like this
http://store.summitracing.com/partde...5&autoview=sku
or this
http://store.summitracing.com/partde...5&autoview=sku
or simply an open diff version of the internals.