There are many factors that influence how any automobile performs. They can include, but are not limited to, maintenance, quality of parts, quality of assembly and driving habits. Since maintenance and driving habits are the sole responsibility of the owner/driver of the car, the quality factors can be out of the hands of the usual owner. The parts quality and attention to detail during assembly are the responsibilities of the engine builder. The interaction each component with the rest is critical in how the engine will behave and live. In the case of the Type 4, we are fortunate in that, for the most part, quality among the parts being offered is good. The Type 4 has yet to get tons of questionable chrome pulleys and cast iron crankshafts. As someone interested in Type 4 engines you are looking to get the best value for your buck.