Although the other retail sites for the coupons also give similar discounts, becoming a member of the main site gives you an added advantage by way of discounts and offers. With the e-mail alerts, you will get the latest news in terms of discounts and promotional sales, which is excellent if in case you have in excess of one car to maintain. The 10% discounts may seem small for a few parts, but in terms of having to acquire several parts and have the car serviced too, then that may be where the real savings come in.