The electronic one retards when it is energized by the emission controls (same deal as the O tdc timing). Are you wondering about the differences or is your can shot & you are wanting to replace it? If so I'd suggest a regular (non electric) one and CCW with the 3/32" allen wrench slows the curve (doesn't change the total the can offers which is as said the number stamped on the arm) by requiring more vac for the same amt (deg) of advance. You can file the notch in the arm for more advance and epoxy strips of feeler gauge with JB weld on the back of the can to limit the arms' travel into the can to limit the total (either way as needed). I would set the initial then the total (initial+slots/no can) then springs then hookup/adj the can and (A) you want to stay just under the pinging point on your hottest/driest day at a steady (high vac) rpm such as an interstate cruise at or above the RPM where the springs are maxed out (full mech/vac adv) by altering the arms' travel then (B) with the allen wrench let the can come in as fast as possible staying just under the pinging point on your hottest/driest (most likely to ping) day in everyday driving under varying vac levels. alot of work but alot of gain to be had