104 ignition system has the resistors built into the plug connector/boot, so... adding a resistor plug only taxes the coil.
The coils on these sytems fire 2 plugs , in series. [waste spark system]. Adding resistor plugs can be a burden on the coil as now the system has to travel through 4 resistors . [ 2 connectors/2 resistor plugs.]
The wasted spark has little draw off the system b/c the piston is not on the compression stroke, but the resistance of the plug does , regardless of which stroke you are on .
This is also something to consider when using larger plug gap than spec .. [ the 2 plug/per coil series circuit means the spark has to jump the total gap of BOTH plugs...so it is double the distance/gap..]

F8DC4 Bosch Super is the called for non-resistor replacement .