They are technically not mechanical since they contain switches and wires in the electronic path, but they are not regulated like a Provari is. They have a lower voltage drop than the current metal Reos. Lower Voltage drop means less of the battery's energy is wasted trying to get to the coil, so the coil sees a higher voltage.
I have not tested everything but since they appear to use the same springs I'm guessing the larger contact patch on the positive battery post is the main difference. Copper wire soldered to the positive path might also be more efficient than the firing pin in the grand. Copper wire is used for the negative path instead of the aluminium body, but the mass of the body should make up that difference.
This will change when the supplier Rob orders from comes through with the parts for the Grands.
