Deciding to upgrade the TRX-4M Defender in several phases, the first batch of upgrade leaned towards tweaking the cosmetics, which ended up tuning up the suspension. 53mm shocks in red, stainless clearance links, and negative offset aluminum wheels. The red showing inside the wheel arch when the shocks stretch is a cool-to-see.

Though I did order steel drive shafts, a change of mind made that upgrade pending. Instead of upgrading the drive train and steering part by part, I decided to build up the front and rear trans-axle unit completely with gears and bearings and brass parts before fitting them in. Mixing plastic parts with metal parts doesn't sound good balance-wise. Also to be honest, repeating the tear down and build up again and again for each part upgrade would at some point become more bothersome than fun. So, now waiting on the second batch or parts below so I can do a complete trans-axle build.
The build up should be fun. 　

Compared to the FMS LandCruiser 80, the TRAXXAS TRX-4M Defender has more torque and better suspension damping which leads to better terrain traceability even in stock. It does seem to need more clearance, and the dampers sometimes cause fixation which is motivating me to consider upgrades. A little at a time, so see what's working and what's not.

While searching for the FMS 1/18 Land Cruiser, I learned about the R/C manufacturer TRAXXAS. Many after market parts from various parties, good performing models make thei vendor a classic manufacturer. The flagship 1/10 scale Land Rover Defender TRX-4 overwhelmed me at that time, (here and here）, but the size and budget was too much for me.
A 1/18 scale crawler has come out from TRAXXIS, with the model name TRX-4M, which can be referred as the 1/18 version of the TRX-4. It seems to be out in the market for a while, but still difficult to get in Japan, as well as Europe and the US as of Jan.2023. Searching online, I discovered a green one I've been wanting n stock at a site in Germany, and ordered it as a partner for my FMS LandCruiser.

Lined it up with the FMS Land Cruiser.

Radio controlled (R/C) cars has been my hobby for a while, and I've been building ones, running them, then trashing them. The latest one is a Formula 1 six wheeler I built more than 5 years ago, but it's been sitting in the "garage" for a while now.
The issue with road going R/C cars is that there are few places to run them. With low ground height and short suspension stroke, it's difficult to enjoy the ride unless you run them on a really flat and clean paved area. Since there are so few of them around, the cars end up stashed in the closet.
So, off road crawlers. They're made to run off road, up hills, rocks and even muddy areas making full use of the suspension. A different way to enjoy than road cars, and no need to look for flat pavement. A lot of tune up parts add on to the enjoyment.

The model I chose for my first crawler was a 1/18 scale Toyota Land Cruiser 80 scale crawler from a manufacturer called FMS. As rumored, it's degree of perfection is quite high and well built, and a good moving suspension with four wheel drive.

Running it in rough terrain showed it's potential with long legs and sufficient torque, but I also learned it challenging to make it climb up and down tricky areas avoiding a rollover. Yes, challenging, and fun.