Have any of us in the V6 community ever thought or tried upgrading to a posi and/or change the ratio? If so where did you get it?

So I'm gonna go ahead n throw those kooks lt headers on with that slp loudmouth 1 setup, & I decided next on the list was the rear differential. Anybody know if there's a posi (limited slip) rear for 2012 models & how much they run?