Shares of the used car specialist have staged a massive comeback over the past 12 months. What might happen next? Carvana (CVNA 5.85%) has emerged as one of the market's biggest turnaround stories, with shares up more than 800% over the past year and more than 35% since the start of the year. Those kinds of gains garner a lot of attention, and investors are particularly interested in insight on whether the rally will continue. Is the stock a buy now, or will Carvana's path hit a dead end? An improved financ ...