Sorry for adding on with my own questions in regards to calculating damage.
When calculating damage, can you use the surges before subtracting shields on die rolls to add to the total damage, or must you deal damage first before being able to apply surges to buff an attack?
All damage from the attack (including that added by surge effects or other hero abilities) is totalled before subtracting shields rolled in defense. Surges can always be spent if they have been rolled, provided you have something to spend them on.
The only thing that is conditional upon wounds being suffered by the target are Conditions (Poisoned, Immobilized, Stunned, or Diseased, in the base game.) That is all.
So, supposing you had a weapon with the ability "(Surge): Stunned" and the target has rolled sufficient shields to negate all damage. You can still spend the surge on this ability if you want to, but the target will not be Stunned because he didn't suffer any wounds. I'm not saying it would be wise, but the point is you can always spend surges.