A lot depends on if you get a 2000 - 2004 model (First gen) or 2005+ model (Second gen).

The 2nd gen can mount 33's with no mods except melting back a little bulge in the plastic front wheel well liners...and has an extra 100 HP or so, plus gets better mpg...but costs more.

The 1st gens are of course at least 9 years old for the newest of them, and cheap...and need a 2" BL or front fender mods, etc, to fit 33's.

The diffs on the 1st gens are tough 3rd member designs, with the rear diff being between a ford 9" and a Dana D60 in strength.

The 2nd gen diffs are aluminum, and, the rear is a D44 hybrid...which for the OR model, can come with a locker.

Depending on your budget for the purchase, the recommended mod and reapir parts lists are different.

What did you have in mind?