With sales tax and now some of the internet heavy shops offering free shipping, it hard for the local shops to compete. Especially shops not on the west coast. Places like Prostreet Online can go down to the big distributor warehouses and pick up their HKS and Greddy parts and then sell them with free shipping and actually make some money. If somebody wants some simple part that you don't have in stock and it has to come from the west or east coast then it's often easier just to tell them to order it online. There isn't much markup on import car parts nowdays(not that there ever was a lot, except by Extreme Motorsports
) when dormroom parts slingers like Darkside Racing sell parts at $10 over cost, so any profit can often be totally eaten up by shipping costs, unlike in the car audio world where the markup for the vendor can be 100%.