I've got 35's and think that spending the money on them and not 37's was the worst decision that I've made in modding my JK. I do have the Rubi with D44 up front. I've been getting ready for 37's by gussetting the C2's and LCa's. I've just installed AlloyUSA CM front axle shafts with CTM u-joints and Superior CM rear axle shafts. The CTM ujoints are something else. I think with the above mods 37's would be fine on a D44.

As to running them on a D30.....I don't know......the D44 has a larger ring and pinion and larger Ujoints. If I was going to use it at all hard I'd go to a D44. I've seen buddy's running 35's have problems with TJ's running D30's. But if you have to stay with the D30 I'd go with gussetted C2's, upgraded shafts and CTM's.