In anticipation of a rapid ramp-up in production and deliveries of its 2015-launched Model X SUV, as well as increasing demand for its Model S, electric-car maker Tesla Motors (NASDAQ: TSLA) went into 2016 expecting impressive growth; Its full-year guidance implies about 68% year-over-year growth in vehicle deliveries. But a slower-than-expected start to 2016 may have investors wondering whether the company’s will be able to follow through on the rosy outlook.