CarMax (NYSE:KMX) delivered record first-quarter results today, sending its stock up more than 16%. Management attributes the success to sticking to its plan of controlling costs and providing an excellent experience for car shoppers. 

Store traffic increased, driving the higher sales across the board: Wholesale unit sales, used vehicle sales, new vehicle sales, and CarMax's financing arm all expanded over the quarter. Stock Advisor analyst Sara Hov and Rule Breakers analyst Simon Erickson talk about how the company is executing on its strategy and what the outlook is for the company -- and for investors.