I would try and keep close to the stock stagger if possible. In other words, up the front width to go along with the wider rears. To maintain the rear civilized I've found -.8º camber and 1/8" toe in (total) to be kosher with 285's. I've never tried less negative camber or more toe in but I've tried everything in the opposite direction. My car is lowered quite a bit and I need to get some adjustable sway bar links made. As it stands the bar has lots of preload and I imagine all the lowered Crossfires do too. I mention the bar preload because I believe it affects the rear grip in the corners. Speaking to track junkies with adjustable sways, they tell me softening the rear adds rear grip so a "tight" rear should result in a loose rear. Food for thought. The biggest problem I had with the open diff at the track was spinning the inside wheel and traction control intervention.

Les