I'd probably not go over 3.73 on 33's and the auto. You want the RPM's below 2500rpm at 65mph, as close to around 2200rpm as possible. 4.56 is too high of a gearing, you don't want to be rolling near 3000rpm at highway speeds, do you? That's where the 2.5L likes it, not so much for the 4.0.
31" tires throw the speedo off by about 11%, so you're doing 2500rpm at around 60mph.