Dont put money into those stock axles!!! If your gonna do it, do it right from the beginning. That's why the only thing I've done to my rig in a long time is the steering Troll pirate4x4.com and keep your eyes open. There are literally thousands of write-ups on lifts, driveline changes and axle upgrades/swaps. If your gonna roll 33's, your factory diffs can handle it, even locked, if your easy on the throttle, but a 7" lift? That'll throw your COG to the moon. you'd better think about a cage being that high up. Just kidding, slightly. Also, don't worry about truss'in the D30 unless you plan racing this thing in the JeepSpeed challenge or King of The Hammers. Also watch craigslist and Pirate4x4 in the "for sale" section of their' forum. people are always ditchin their junk for bigger stuff. I've seen probably 3 or for TJ and JK D44's go for next to nothin just this month alone. Not sayin D$$'s are gonna be the best longterm option if your gonna roll 37's or something, but they will last longer than transmission if you only run 35's or smaller, plus, other than a 8.8 rear end out of a Ranger or Explorer, they are probably gonna be the easiest to modify for you ZJ's needs. That rig does not need 7"s of lift unless your going to roll 35's or bigger. Not trying to piss in your cherios dude, but i'd really hate for you to put in all the $ and time to just be disappointed with the finished outcome.
Another $.02 from The Bank of Swagger.
PS. Read EVERYTHING you can on pirate4x4.com. The yahoo's that post their junk on there are stupid talented at what they do, and there's so much info there that a person could build a no-shit, all jokes aside comp rig from start to finish on their first ever build, AND compete with the other rigs in the amateur and pro-am lines of competition.