While I still believe these things will make ZERO difference on power or how well the car runs in comparison to GOOD factory coils (except in people's minds), I would not expect it to be normative that you lose power either. At worst, these aftermarket coils would be like aftermarket coils on other platforms . . . equivalent performance with less longevity. At best, they are equivalent performance with equivalent longevity . . . and nice aesthetics.
Point being, even as a doubter, I would conclude you either have a bad coil (or multiple bad coils), or something else is going on.