honestly a good set of bump out sliders and skids with
maybe a front bumper is all you really need. i wheel the ever living piss out of mine and my skids and sliders show it. i do have some rear quarter damage but thats because i didnt get bump out sliders (which i regret). and honestly the plastic cladding down the sides is pretty robust and has come in clutch for me a few times, as in held my truck up against a ledge/wall when i sorta kinda laid it over. all it did was gouge the shit out of the plastic and thats it, no door dent or any thing. if it was say ny dads 5th gen it would have wreaked the door.
now if you really feel the need for rear armour the 4x4 labs bumper is the titties and can be configured to include more rear quarter armour.
This is my damage after i laid it up against the wall when wheeling it in east Texas
This is after i leaned it over into a tree that some bumpout sliders would have saved me from
another point to raise is adding a ton of weight to our 4th gens and then wheeling the piss out of them is not the best of ideas. we're still on the original 8"v6 rear end which is already stressed enough with some of the hard wheeling some of us do, ive seen plenty of 4th gens and early FJ cruisers strip ring and pinions and simply blows diffs up. this was at least partially remedied by toyota going to the revised 8" differential referred to as the 8.2, its about 15-20% stronger in the deflection aspect as torque is loaded to it compared to the 8'v6. so there is that to think about as well.
The best bet you have is if you really want to wheel the piss out of you 4th gen is to get a good set of bump out sliders, a good set of skids(front, trans, tcase, fuel tank, and rear lower control arm mounts), maybe a front bumper. then invest in suspension and differentials. i have Metaltech long travel rear and a homebrewed front that maximizes the travel from the stock geometry as well as a OEM elocker retrofit in the rear. travel and lockers help prevent you from throwing you truck in to everything and over working it and risk breaking things.
this is mine on a 20degreee RTI ramp to show you what a good set up can get you
Thats 38" of total articulation on 35x12.50s and a rear locker. keeping all 4 on the ground helps keep you out of risky situations that could lead to serious damage with much less weight than throwing plate steel at the body and YOLOing it.