Really don't matter on the size of Magnets or Crystals,They don't work!!
I'm a little skeptical about Plug and play items that clam to be the answer to More Power,All Around Performance and Fuel Economy!!
If your fooling the ECM to do things differently than it is programed,Your Not going to gain at 1 point with out loosing somewhere else in the full spectrum,If there were a way to do it the manufacturer would have done it!!
They spend Big $$$$ testing for this type of thing!!
There programed to self adjust to get the best they can do for All Operating Conditions/Ranges!!
Sure,you can make one have a little more at say 90* in south Florida,but what happens when you go visit Uncle Joe in Denver and it's -10*??:L
The car ain't going to start like it would in Florida,Probly sputter and die 5-6 times till you get it going,undue ware and tear on components among other things!!
Besides,I have a customer that has some sort of little black box on his C4,and it does make it have a little extra noticeable performance!!
But the down side is,It uses more fuel and seems to fry TPS's and O2 sensors a couple times a year!!
I'll just leave mine like it is,Becides if it ran any better or got any better fuel economy,I'd have to give up Sex!!