There are no Tx/Rx upgrades for HL tanks.
I think Darkith's DBC RC2HL DOES work with regular RC Gear. $55 ain't bad vs El Mod $$$$$$
For use with the stock Heng Long Smoke&Sound ESC/sound board, and standard 4-5 channel RC TX/RX (27mhz, 40mhz, 50mhz, 72mhz, 75mhz, 900mhz, 2.4ghz). Great for replacing the stock 27mhz radio with your own computer radio, and permits more tanks to battle together!
http://darkith.dyndns.org/~darkith/html/dbc.shtml