First thing that I have to ask is which RX-7 and which igniter?
There are 5 different igniters that were used on different generations of the RX-7.
As for them causing the coil to put out more spark, No. On any and all inductive discharge systems, the coil only puts out what is requiered to jump the spark gap The igniter basically justs turn on and off the charge to the coil based on the signal to the ecu and in some situations, also controls the dwell time and that is it. An igniter is used cause the ECU can not handle the charge current involved. Just because you have a lets say 50,000 volt coil does not mean that you are getting that 50,000 volts. If only 15,000 volts is requiered to jump the gap, then that is what the coil will provide regardless of what it is capable of and the igniter that is being used. During the coil dwell, the coil keeps building charge until one of two things happens, either enough energy is built up to jump the plug gap or the dwell has run out, period, end of story.... Running a different igniter from a different car is not going to increase the coil out put unless it happens to be a CDI (capasitive discharge) unit, in which case, is a different story but none of the RX-7 igniters are CDI, so no change is going to happen.
