I did a search for this and came up with nothing. Searching "resistor" found too many to search through.

Which resistor should be used in the PMD/FSD? I've seen #5 and #9's
What's the difference?
Can you run without one at all?

Getting the old resistor out is a booger. I'm thinking that if mine dies on the road (I have a spare), can I run the new one without a resistor if I am unable to get the old resistor out at the time?

Should I purchase a new resistor? if so which one and why?