Subaru's announcement for the 2007 STI Limited says that the car will now have a Torsen limited slip diff, which is a change from the viscous setup that Subaru has used for years. I don't know much about the Torsen diff, other than that a lot of other manufacturers use it on their AWD vehicles, including Audi. Anyone know if this is a good thing, or what the reason would be for the change?