But if you actually take it off-road very much, you would not want a heavier duty suspension. You want as much flex as possible.
Tow package...I just bought a 15,000 lb hitch the other day for $40.
Shocks, anyone that's seriously into wheeling know where the good deals are on them.
Locking differential...that is worth something, if it's a locker. If it's just a limited slip/posi, what's the point??
The tranny and oil cooler might make it worth it (with the other stuff combined) until you look at what a wrecking yard has to offer...where you can build your own for very little $$$.
Just to let you know, I'm not argueing with anyone at all...I'm just trying to make a point...half joking around (even though I am serious about all that stuff above).