Back on topic...
31x10.50s on the original rims should fit fine. I ran 33x9.50s on my YJ with the stock 15x7 rims.
Springs.... an SE is pretty light up front. Anything "Sport" rated will ride rougher in an SE.
30/35 combo?? 31s and the 4 cylinder should be fine with the stock axles. Especially with 4.88s which will reduce the stress.
BUT owning a TJR... I'd recommend selectable lockers to anyone, everytime. They will be the most functional, useful mod you ever do.
31x10.50's should fit just fine, with maybe a little adjustment to the steering stops. I understand that they may run a little close on the inside, which makes me nervous though.
True, the SE is pretty light in the front, and I'd like to keep it that way. In fact light is a build goal. Learned that from long distance back packing...ounces add up to pounds which reduces performance and increases injury rates. I've got 120 HP and140 ft/pounds to work with. That's a tight performance budget right there. The SE is light in stock form at 3,200#, but it wouldn't take much to blow the hp to weight ratio right out of the water. Heck, I'm even investigating aluminum replacement skids and bumpers to see if the weight can be reduced from stock. Delivered some parts to one of the fab shops in the facility last night and the sight of all the aluminum stock and forming machines got me to thinking. I'm betting that you could drop 300 to 500 pounds from a stock TJ in a weekend in there. I'd loose my job, but I'd have the lightest TJ on the block!
It's one of the reasons that lifting an SE is such a challenge as well... Almost all after market spring sets are set up for the six, which is notably heavier. A nominal 2 - 2 1/2" lift usually results in anything from 3 to 3 1/2" of realized lift on an SE and a rougher ride from higher spring rates. The exception is OME, where they have a whole selection of spring rates, and even differentiate between passenger and driver side. You pay a premium for that kind of expertise. The difference is the cost of the TruTrac for a Dana 35. Choices, choices.
I think so as well, and will run the stock axles for awhile in any case. Being a belt and suspenders kind of guy stronger axle shafts will probably go in later. We'll see.
Oh man, I've agonized over the selectable locker decision... That just opens up an expensive ball of wax for me. For the time being I think that I'm going to have to live with putting a limited slip in the back. Someday Dana 44's with selectables may be in the cards, but I really don't want to wait it out for a couple of years without some form of traction enhancer. I can get a TruTrack for $400, and have it installed when I do the gears for no additional charge. An Elocker, which is my preference at the moment, runs about twice that, plus rounding up a Dana 44 around here to put it in about doubles that. With upgraded axle shafts and etc., I am in the ball park of a new, factory fresh Dana 44 with all the goodies from ECG or G2. The whole build / buy decision tree comes into play to the tune of about $3,000 +/-. So, a Revolution Super Dana 35 kit + Selectable Locker + axles and install parts or a Dana 44 with the same thing or a crate Dana 44 set up and ready to bolt in. Any way you look at that, it's going to run anywhere from $2,300 to over $3,000 per axle. No way to do that right now.
Thanks for the input billiebob, I appreciate it. Your suggestions are sound and I would implement them except for the cost of doing so right now.