Carmax (KMX) has been on fire lately. The company has shed a weak auto industry and just chugged along, producing staggering results. I'll be the first to admit that I wasn't exactly bullish on KMX in the past as it suffered from lower prices and margins. But those things - as evidenced by the Q2 report - are things of the past and the stock is rightfully hitting new highs. Given the fact that new highs are being hit, is the stock worth chasing here?