Any time you see a "magic box" for sale, it's time to do some extremly heavy research before buying it.
When they give you a box and say it works such percent better, then just repeat the sales drivel every time you ask what it actually is, that's a bad sign.
All that bat-pac is is a large capacitor in a box, I think. I cant see it being anything else.
This doesnt neccisarily mean it wont work... But at $55 for a $10 capacitor, or $12 for the actual honda battery, I know what I'd do.