With almost 4,700 retail stores in the U.S. and Mexico, AutoZone ( AZO) weighs in as the world's largest aftermarket car parts seller. The firm is another major beneficiary of consumers' trading down -- as credit markets seized and new car sales stagnated, AutoZone actually saw sales increase as consumers sought to keep older cars running. While that structural advantage has been mitigated by negative real interest rates, and aggressive incentives by car dealers, AutoZone is still generating strong sales numbers. International expansion is one attractive growth avenue for AutoZone - and expansion to other markets seems like a logical progression for the firm. Another area of growth is the firm's entrance into the commercial market, selling parts directly to garages and dealers. In the commercial market, AutoZone is a small fish in a big pond; it should be able to secure near-term growth merely by taking share from some of its competitors. With analyst sentiment rising in shares of AutoZone, we're betting on shares of this Rocket Stock this week. AutoZone shows up on a recent list of 7 Low-PEG, High-Momentum stocks. To see all of this week's Rocket Stocks in action, check out the Rocket Stocks portfolio at Stockpickr. -- Written by Jonas Elmerraji in Baltimore.