I think what gets lost here is the fact that not only does the coil need to withstand the additional voltage,so does the switching device! Take a 1 ohm coil,at 9 volts, when the switching device(points,ecu,etc)turns on(pulls coil- to grd)the current flow thru the pri. windings(and the ecu)=9 amps.Same 1 ohm coil at 14 volts,when turned on(coil- to grd.thru the ECU) will flow 14 amps!Remember(on a v-8) the coil has to fire every 90 deg. of crank rotation!Current flow=HEAT!But that heat affects not only the coil but the switching device!!!If you want big spark,switch to a MSD type ign. Big reason the OEM's went to COP,more charge time and more cool down between firing!I wonder if all the failed ECU's are due to wiring issues more than quality control?