I'm heading into the shop to finish up the recoil modification for a KV and KT using David's DBC-RC2HL. I'll post a tutorial on the recoil modification and using David's DBU and the HL Apple. It's a very inexpensive modification as the DBC-RC2HL and DBU cost $70 (you need a rc radio for the DBC-RC2HL board). In addition to David's electronics, you will also need to purchase a PICO switch to power the recoil system. However, by using the DBU and placing it INSIDE the TURRET and running the LED's to your periscopes or similar locations on the turret - you can use one of the sensors from the DBU and replace the sensor in the Heng Long Apple (the Apple has no LED's). By using the HL Apple, you will save another $80 plus.
Your total cost is about $100 dollars. On my HL KT, I just received an Impact Apple which is similar to the Tamiya, but cost considerably less. I'm mounting that today for DAK's battle next weekend.
tjs