depends if you have a 4 or 5 wire box. if you have a 5 wire box, you're supposed to use a dual ballast resistor... a single one for a 4 wire box..
http://www.allpar.com/fix/electronic-ignition.html
just make sure you don't hook the coil up backwards, I did just recently.. still ran, but wouldn't rev over 3,000 rpm... but you're probably much smarter than me, and wouldn't make that mistake :)
-j