I would love to see the clearance under an 8.8 on 31s. Maybe you could just put an anchor back there, it would cost less, lol. One option that I haven't heard anyone mention is to keep the D35 with your current tire size, leave it open, and put the lockright in your front axle. I've wheeled on a locked D30 with 35s for about a year and a half now with no problems to date. Having a locker in the front may be all the extra traction you need for now, and will certainly open up new possibilities to you. What everyone is telling you though is absolutely right, the D35 is not worth locking, and is really only good for short term use. However, if you keep your Jeep with smaller than a 33" tire and leave it open, you will probably be fine for quite a while. If you ever want to go any bigger, you should really start looking for a swap. There are guys over on jeepforum that claim that the Super35 kit when properly installed will hold up extremely well, but it is simply not an axle that I would want to spend anywhere near that amount of money on. Just my .02