Overview: Need a car part or an accessory to give it personality? Since 1903, when Sears dedicated a portion of its catalog, the automotive after-market grew into a billion-dollar juggernaut. We visit Auto Zone, the retail leader, whose largest store carries 25,000 parts. At SO-CAL Speed Shop, a sedan is transformed into a hot rod. Achieving $100-billion in annual sales didn’t happen overnight, but largely on the shoulders of three entrepreneurs–cartoon characters Manny, Moe, and Jack, who were real people. In 1921, they opened their first store in Philadelphia–Pep Auto Supplies. By developing brand names, carrying key parts, and providing hands-on service, they set the standard. Finally, we look at odd products sold by auto stores, discover how Armor All transforms dull interiors into brand-new, and how a tire sealant named Slime may replace the spare tire.