Here's my HL Challenger 2, it was purchased and given the basic minimum equipment a few years back as an exercise in assessing how cheaply a Heng Long tank could be made IR battle-worthy. The cheapest variant was purchased, with plastic tracks, plastic gearboxes etc. and fitted with Clark TK22 along with a Clark recoil unit and the necessary Tamiya IR battle apple and IR emitter (a Tamiya
JS-2 clip-on).
For such a large tank it was surprisingly light as a result of the lack of mods but the plastic tracks stretched after one full game day and there was no track adjustment available, and I reckoned I was in for a penny and in for a pound. It ended up costing as much as a regular Tamiya 2A6 but well, Tamiya doesn't make a Challenger 2 (yet).
I am a big proponent of proper serious hobby grade RC tanks needing track tensioners and this is my first priority. These are very well made (milled) and if it wasn't for scale appearances I would have left them in natural finish. They did cost a pretty penny, as much as I had spent on the entire tank up to that point.
The front mounted idler is fairly weakly reinfoced especially if DKLM's tensioner has to be fitted; my builder had the front corners braced in preparation for installation.
The stock molded plastic idler is completely shaved off and replaced by brass parts.
The system uses a prototypical cam design to micro-adjust track tension precisely as needed. I have had no track issues since, but Tamiya's hybrid material tracks are one of the best around.
The front idler wheel is also metal and features a hub cover that is magnetically secured.
My memory is hazy on this but I think I did have to buy rear drive sprockets that would work with the 2A6 tracks (also from DKLM).
All in all, the Challenger 2 is a decent running tank, which was why I could justify the additional spending on it. I don't run it all that often, only because I am unfamiliar with the Clark TK22 operating methods. I'm a simple guy and like straightforward Tamiya-style controls. The Clark gun recoil gearbox later broke down too, and I upgraded that to a DKLM full metal setup as well and after a battle I had lost the cupola machine gun and ended up purchasing a SOL Model FN MAG which was made out of resin but was much more highly/accurately detailed.
Oh and the tank is painted in the markings of "Arethusa", depicted as it participated in filming a mock race across a firing range against a Range Rover for the TV show Top Gear. In actual fact there were several Challenger 2s used but Arethusa was shown most prominently for purposes of reference.