I believe that we must do the right thing for our tires. If the outside shoulders get corded, then you need another set. -2.8 should do the job in front and -2.5 in the rear. You will need a certain amount of toe in in the rear just to prevent some bump steer into a toe out mode. As your rear suspension goes through the arc from bump to droop, you do not want a bump steer happening at the apex, with throttle on.