ORIGINAL: funflier

where is the toggle installed in relation to the circuit as I cannot think of any automotive toggle switch right off that is designed to handle say 20A DC (thats why they make relays). As for a bec or a UBEC (stepping bec) it will make no diff at all on either the temp of your esc or your run time, unless your into a heavy digital setup. and the the extra 10 seconds more or less is really hard to cound.
If you wanted to make your esc run cooler you can do more for it by cutting off the cover just around the metal heatsink, and installing a heatsink. If your a fanatic like me and have too much time on your hands you measure the temp with a probe of the ESC with and without a UBEC after you run it full power on a bench... I have a link somewhere on the specs on one common ubec and will will look it up and post it.
Mean while here is a link to the people that probably know more about it then anyone do far down there.
http://www.dimensionengineering.com/ParkBEC.htm
BTW Zimatosa took his ubec off as it was just extra weight.