Bill,
You can convert your running lights to LED without any issues or resistors. Resistors are only needed on the turn signal circuit because the turn signal flasher needs the resistance of the light bulbs (the load on the circuit) to flash at the proper speed. Without normal bulbs in that circuit, the flashers flash to fast...requiring the addition of resistors to slow everything down again. To me, adding resistors to the circuit is a waste since they have the same current draw as the light bulbs...so no gain there.
However, if you add LED turn signals to your existing bulb turn signals, no resister needed since the bulbs are still in line with the flasher. That's what I did when I replaced my front and rear side reflectors with LED lights and attached them to the running light circuit and the turn signal circuit. They run all the time and blink when I use turn signals.
Bottom line:
1: Adding LEDs to your existing turn signals is fine...no resistors needed.
2: Replacing your bulb running lights with LED's is fine as well. No resistors needed.
By switching out all your bulb running lights with LED's, your electrical load will drop a lot.
Last...there are LED replacement bulbs on the market that simply plug in to your run/brake light in the rear. That results in a brighter light that uses less power.
Fool's little circuit board will add a flasher to that system so his brake lights will flash when applied. We can buy those flashers for incandescent and LED bulbs as well...he is saving bux and getting exactly what he wants by building it himself! Cool...
Hope this helps,
david