I've tried a few different setups. Right now I'm running a 265/285 setup on 9.5"/10" wide wheels with an RS1 suspension setup (500/800 lbf/in spring rates). Getting ready to install a 3.62 FD diff so I might bump the rear up to a 295
I'm very happy with the current balance, however, it's a function of ride height, damper settings, spring rates, and alignment settings so it might not be the "best" for everyone - took a little bit to get it dialed in to the way I like things. I'm assuming the new diff is going to result in a few adjustments to the current setup, including tire widths/stagger.