Should GM fret at the thought of Tesla? The Big 3 automakers had sneered at electric vehicles (EVs) for years, but a slow shift is underway. Ford has its plug-ins with the Fusion Energi and C-MAX Energi; Chrysler, thanks to Fiat, has a little toe in the EV waters with the 500e on California roads; and GM touts the Volt and Spark EV.