Pretty new at this but here goes, I own a '99 TJ four litre with a 35 rear and 30 front, looking to beef things up on a budget, i'm thinking a ford 8.8 out of a 96+ explorer for the rear, but for the front im not too sure what to do, i'm looking for a swap that's not gonna break the bank or going to require crazy fabricating because this is gonna be my first crack at something like this. Real jeeps are built not bought....any help is much appreciated.  

If you run smaller than 35s your front 30 will probably do fine if you don't get crazy or do a lot of rock crawling. A TJ Rubicon D44 is not a whole bunch stronger. It shares the same tube size and outers as a TJ D30. The diff is stronger but that's not usually what fails with the D30.

The Ford 8.8 is a popular swap, strong and gets you disc brakes. It also takes some fabricating for the mounts and some creativity for the e-brakes.

If you are planning gears and lockers then a new TJ D44 housing from Chrysler ($500) will bolt right in, and uses your existing brakes.

If you need to change gears in the 8.8 then I think the TJ D44 is the way to go.  

id run the d35 til it breaks. then i would think about changing the axle. not as immediatley rewarding as swapping the axle, but would be easier on the bank. friend of mine has a ford 8.8 and beats the snot out of it, no problems yet.