Where are the tires rubbing? Fronts, rears, inside out? Under flex?

As far as lowering the diff, I plan on it, but haven't experienced any real issues. There was a time on the highway in Colorado when I had the front engaged and speed was at around forty and the vibration was bad, but that was the only time I noticed it. I think the steering is a more timely upgrade, at least it will be as time passes for you.