There was a time when Heng Long were what you would expect from a Far eastern Toymaker,
Times change,
The latest 2.4 digital Heng Long Radio Control Tanks electronics are coming up to the standard of aftermarket control boards, They aren't there yet but they are miles better than they used to be,,
The ABA used in the construction of the Tank is sturdy and not at all fragile like the plastics of yore,
Where I would be looking is the Gearboxes and the smoker.
Certainly if you are confident enough to do a little tinkering then I would unplug and unscrew the Smoker and replace it with a "TARR"/1/2/3/4 depending on whether you want a metal body or plastic Proportional smoker or not,
A Taigen 4/1 or 5/1 gearbox would be my first choice in replacements,
Again simply unplug and unscrew, of course you will need to remove the tracks but that is easy enough.
After that you should have a Tank that will wipe the backside of the pain across the road.
The gearboxes should be readily available from IMEX in Florida, but I don't know of an American source for the "TARR" Smoker I buy mine from ---
www.rctankelectronics.com
And click on Store for details on the differences between each one,
And remember with the £ dropping faster than Donald Trumps popularity now's the time to buy from a British dealer!!
Oh and welcome to the world of Radio Control Tanks.
Shaun.