You have come to the right place,
Gary (Max-U52) Is one of a number of top quality men in your country,
The Best Dealer for your upgrade needs will be -----
http://www.imex-model.com/
and the RC Tank Man in that store is "ERIC" They are based in Florida and have a very good reputation amongst the RC Tank fraternity in the USA.
They specialise in all things TAIGEN and Most TAIGEN Upgrades are good for Heng Long Tanks,
Fitting Tamiya Electronics in a Heng Long Tank is a bit like gold plating a plastic wheelbarrow,
There are some very good aftermarket Control Boards (MFU) that are much better than Tamiya's and are compatible with Tamiya I/R and a great deal cheaper and more user friendly,
Just some are ---IBU, ASP, Elmod,and Clark, there are others.
Heng Long used to make I/R Tanks but it was not compatible with Tamiya I/R and as the international rules of Fighting Armour in Radio Control stipulate it must be Tamiya compatible Heng Long stopped making theirs and now concentrate on Airsoft.
So now everyone fighting with a Non Tamiya Tank and that includes Taigen fits one of the Boards I have mentioned.
The Tiger 1 has more aftermarket bits and pieces available for both Heng Long and Taigen Tanks most of which are interchangeable. Batteries and Chargers have managed to split the modelling community over recent years,
Some including me swear by Li-Po Batteries others swear at them.
They take up a lot less space for the equivilent output of a Ni-Cad , BUT you need a much better charger than the factory provides to get the best from them,
My own is a "Turnigy Accucell -6" from----
www.hobbyking.com/
which is an international company.Shop around for the one that suits you but do make sure it can Charge Li-Po/Li-Fe as well as Ni-Cad/NiMh batteries.