You spend a lot of time and money trying to get customers into your shop, which makes it important to earn their repeat business. You can’t do that, though, if the parts you use are substandard or flawed. Your customers will be able to tell the difference, because their vehicles will not perform as well as they should. Their vehicles may also breakdown prematurely. By not using OE quality parts, your profit margins might be higher over the short term. However, if over the long run, you want happy customers, repeat business, and sustainable margins use OE parts.