Heng Long is getting out of IR, but I didn't know they were already that far.

You need an emitter and a battle unit (receiver/apple/mushroom) to convert to IR. Also a flash unit. Most guys do barrel recoil but it's not strictly necessary to be IR ready. I'm about to put an impact unit in my Tiger One but it was an IR tank to start with, so I have a head start. One nice thing about the IBU is that the Impact and Tamiya (TBU) plug right in. You'll have to mount the base for the battle unit, and install the emitter (usually in the mantlet, maybe where the airsoft warning LED is now) and also the flash unit in the barrel. I've heard of guys using the old airsoft unit and hollowing it out to pass the wires through and still keeping elevation intact, but you may be able to do something with one of the existing IR units. Someone more familiar with the KVs should know what fits best.

I think that's everything, but I'm sure my fellow forum members will speak up if I missed something.