We do to (have those buddy boxes) but I beleive the new Spread Spectrum radios are not compatible with the older technology.

The Spektrum, for instance, will buddy box with another Spektrum but I don't think with anything else. You may want to do a little more research from the manufacturers of the specific radios in question to see about compatibility.

The Airtronics RDS6000 looks just like the RD6000 radio and may be compatible, but I am not sure and will have to check on that one myself.

As for Futaba and JR.. well, I just don't know.

CGr.