Yes, the electronic regulator you bought will work fine. The ignition runs off its own circuit that is powered from the battery (and alternator output). Vreg just touches the IGN wire for "voltage sense" and to power it, but that is a small current draw and shouldn't affect the ignition. The reason you don't want the old mechanical Vreg, is that it constantly switches on & off, causing changes and glitches in the battery voltage, plus some kick-back from its coil into the IGN circuit. An electronic Vreg gives smooth power.