Aniracetam is supposed to mitigate effects which piracetam doesn't. The main neuroreceptor through which this is modulated (among others) is the 5HT-2A. That's about all i know. As far as the rest of it, merely a commentary on the fact that diminished effects are supposed to be helpful in controlling one's intake. A drug that helps anxiety (aniracetam) and tones down the edge of a psychedelic amphetamine would be far more useful for integration of such a substance in one's life than one that potentiates it, but that's just MHO.
It should be noted that the concept of 'mitigation' is also as highly subjective as the effects it describes.