A day after GM (NYSE:GM) announced its March sales missed estimates, 11.8% rise vs. estimates of 19%, the car maker said it intends on resuming production of the Chevy Volt a week early.The company sold a record 2,289 units in March, according to a UAW official.General Motors (NYSE:GM) has potential upside of 34.2% based on a current price of $25.54 and an average consensus analyst price target of $34.27.