I have a 91 FJ80 and I went with 4.56 gears. I chose that ratio because it was perfect for 33's, and for my use I didn't plan on going larger than that tire wise. 33's provide me enough clearance, and I wanted to stick with keeping the spare tire in the factory location (don't want to spend crazy dough on a rear bumper / tire carrier). When I made the choice between 4.56 and 4.88 gears, I entered some info in a gearing calculator, and 33's with 4.56 gears were closer to the stock gearing ratio / tire combo compared to 4.88's and 33's.@marco. I have never been one to think an LC is slow. My previous FZJ80s never had a problem with what ever I threw at them. I would do 1000 mi mountain biking trips with 6 people, 6 bikes and all our gear. Always did 65 to 70 on the hwy with stock gear and 33s.
With 4.88 and 33s it the 3fe should be just fine. Now that I have kids my pro4x is the camper/toy hauler. My 80 is going to be the rig to get me into the woods and go on my personal trips.
Your 80 has a lot of capability added to it and it looks damn good too!
I found the desmog posts. That is going to be top of the list after entire brake system (on order) and failed shocks are replace.
I had the 4.56 gears installed in 2016 within the first 6 months owning the rig. I had done a 100mm OME lift, put on metric 33's on heavy steel wheels, and added a frontrunner roof rack and 2.5 meter awning. After those additions, the stock gearing was pretty bad on the highway, but still fine around town and on the trail. Going to 4.56 gears was a huge improvement. I was living in Albuquerque, NM at the time, so you start at 5000' in town and go up from there. Moving to Portland, OR near sea level was a big 3FE performance boost.
Anyhow, 4.56 is an option to consider. In my experience, 4.88's with 33" tires would be overkill, especially in the Midwest.