The best discount code for enginediy.com is 'DIYMARCH', which provides customers with a 90% discount. Another great discount code is 'H350', offering customers a $300 discount. There's also a code 'DuosEngine' that gives a 10% discount. Please note that terms and conditions apply to these discount codes. It's always a good idea to check the validity of these codes on the official website or trusted coupon sites. Remember, savings can vary depending on the product or the total value of the purchase. Happy shopping!