The main reason for a resistor is not to prevent the coil from overheating, it is to reduce the current to a level that contact points handle.

Be careful. Some electronic distributors can not handle the amperage of a 12V coil. The first 3 years of Datsun electronic ignition could not, and so used a resistor. Older pertronix cannot handle it, but newer Pertronix (I'm told) can do it.

yep when the car is started the resistor is bypassed to give large spark for a few seconds to aid in starting, then drops back to like 8 volts or something like that via the resistor

I too just wired my dizzy to the +&-ve sides o the coil but I used the Bosch GT40R coil just for the hell of an upgrade and left the resistor in place.

It worked well until the dizzy shat itself.

I believe that you can remove the resistor if you change the coil to a non resistor version (ie: steveo's GT40 coil)

I may be corrected here but the ballast resistor just cuts the voltage once the car has started in order to reduce running temp of coil??

Bridge the old Ballast wires?

When i installed my electric dizzy i to disconected and got rid of the ballast resistor all together. i bought a Borsch GT40 coil and it works a treat!

Yep, you need to remove it, the coil needs all the volts you can give it all the time, the ballast resistor works against this theory. I removed mine when installing my electronic dizzy and new coil.

When fitting an aftermarket electronic distributor, should the ballast resister stay or go?

I wired mine straight to the positive and negative terminals on the factory coil and didn't touch the resistor

It works fine!
Are there any Gurus out there to confirm that this is all correct?