I have an 07' 2dr auto, it originally had 4.10's in it and when I went to 35's it became a real pig and overdrive was useless, I put 5.13's in it and it has a better powerband in it than it did with stock gears and stock tires and overdrive is usable again. With an auto I would definitely recommend 5.13's, however Eddie has a point, the pinion for a dana 30 is pretty small and very susceptible to shearing although I haven't had any issues, I'm very aware and prepared now to upgrade the axle if I break it, but thats just me.