The new transponder is just a step in between of 2 systems, when the RC4 system comes the old transponder will become unusefull.
Also the new transponder has fuel resistance wires and has a stronger output signal. Placing it close to the receiver I would not sugest, I have seen many problems with transponders near the receivers. You actually place a transmitter close to a receiver which afects the receiving signal as also other electronics within the receiver.