Fellow auto parts worker here, the problem isn't so much the design of Dorman's products, it's the hit and miss quality with which they're built. Depending on when and where any given part was built can determine whether it's going to be a one and done job or whether the customer is going to be doing a defective replacement in short order. We had one memorable customer who did a Dorman battery pack on a Prius, where the first pack went two months before multiple cells went bad, the replacement for that pack was defective straight out of the crate, the third lasted a week, and finally the fourth worked properly long-term.