I purchased these injectors because I knew each one was handled with American hands and I was not disappointed. Fit and finish are amazing, and after swapping them for the original ones with 200 k miles the difference is very noticeable. Throttle response has improved, the truck starts faster with less smoke, and turbo spool up seems faster with the quicker throttle response. Injectors are definitely a wear item. I found contradictory info on the internet about changing them. After talking with Tim I knew I was making a good decision about replacing them with Accurate Diesel remanufactured injectors. Assembled by an American, not robot in a foreign factory. If I can keep my grin from affecting my foot I will write back about fuel mileage. Thanks again for the technical advise and fast shipping of parts