Above is the EPROM Emulator connected to the ECM's ROM socket. Below is the IC socket I have attached to the ROMulator cable to allow me to connect it to an unmodified ECM socket. The wide pins of this type socket will contact the ECM's contacts without removing the original "RN" positive-retention chip socket.

Of course this would be on the floor of the car with the ECM still plugged into the car's harness, for real-time tuning.