Now it's all fun and games, but beware:
If you install more than 2 of them without reversing the polarity, you would actually be re-misaligning the molecules. This would have the effect of a 0% change and could in no way contribute to anything near a 108% increase.
Now, there was a device we used in the 70's. The Framistat. If you changed it regularly, one could surely expect miracles. That is if you replaced the muffer bearing and piston return springs as well...