So in a demo last night, I came upon this conundrum... Environment card: Power outage (All ranged combat tests in this turn receive a -4 modifier to test value...)

Smart disc Predator throws the disc...

does this mean it needs to achieve a 1-6 instead of the usual 1-10 on a smart disc throw action? I assumed this to be the case, but a clarification would be helpful.

I do not believe so, the Smart disc does not make a Ranged Combat test, it has its own special rules in the Special Combat actions on section Page 30 of the rulebook that details how it shoots.

Remember a Ranged combat test uses the models Ranged Skill with modifiers to shoot.

Smart disc is smart see, it never has mods applied.

Jim, the last phrase in the Smart-disc rule is "A Smart-Disc Throw (A) counts as a Shooting Action."

Earlier on the manual we have this:
"Shooting Action (A) – A Model can spend one Action Point to make a Ranged Attack at a target. When making a Shooting Action, the Model will make a number of RS tests equal to the RoA of the weapon they are firing. The target must be in LOS of the Model that is performing the Shooting Action."

And...

"Any kind of combat allowing Models to attack one another over the distance of a couple of Tiles is called Ranged Combat and requires a successful Ranged Skill (RS) Test."

So, we have "Shooting Action", "Ranged Attack" and "Ranged Combat"... this is a lot of terminology for what probably amounts to the same thing.

The smart-disc is just getting ridiculous... no save, no penalties to hit...

I read it the same way as big jim. It is a shooting action but doesn't use a RS skill test because it has its own special rules. It does make the smart disc very powerfull but can only hit each model once so not over powered