AWESOME!
I own a small 1989er version with the OM314 and I'm still looking for EXACTLY your modell. The long frame, OM364 AND 5-speed-transmission is very hard to get (and usually the transmission is not original, because aFAIK this combination was only build in 1993 or 1994, just before the change from the Mercedes engines to the Toyota engines).
I hope it is reliable as it looks, the engine should be bullet proof. It's the Mercedes 300er series and the OM314 is already great and the OM364 is the better successor. Just change the oil regular (I do it every 5000km) and the fuel filters once in a time and don't touch the injection pump if it'S working fine

It's possible (and very common in BR) to install a turbo on those engines and if you don't increase the amount of diesel too much, it will be reliable as well. The engine was designed for little trucks and the load he has to carry in a Band is pretty little.
The OM364 doesn't like high rpm, see the 2800 to 3000 min-1 as a real limit. My OM314 can carry a little bit more, due to the lower stroke, but only shortly in transient conditions. With the 5-speed this is less of an issue then on my 4-speed. It's not a racecar anyhow.
All up to and incl. the clutch is MB, the transmissions are Toyota. There are little differences from the truck to the Toyota engine (engine mounts), but 95% of the parts should fit.
Regular maint. on the axles and transmission (grease and oil changes) needs to be done like on any other old offroader.
Pls have a close look, how the rear swing arm for the spare tire is mounted, the thin sheets of the cabin will not support the wheight of the tire and canister. There should be a aux frame or something like that inside.
Congrets and I'm jealous for sure, also I live down here and looking all the time.
Here is a link with the Parts Cat.:
CATÁLOGO DE PEÇAS TOYOTA BANDEIRANTE PARTE 1 - https://manuaisdoproprietario.blogspot.com/2019/05/catalogo-de-pecas-toyota-bandeirante.html