Interesting ballast resistor article.

The Crane Cams XR700 I use says to keep the ballast resistor in, unless you have the XR3000 model which was intended for racing (limited life). They don't say if the ballast resistor is to protect the coil, the XR700, or both. I would think the XR700 itself would be OK since there is no ballast resistor when cranking and a transistor would overheat fast. Thus an after-market coil should work w/ no ballast. I'll try later.