Hand built engines are better than the mass produced ones. The ultra high output Honda engines, Ferrari engines, and prototypes are hand built. Tolerances in the mass production line can lead to pretty big variances. SCC's project Celica GT-S apparently made as much power stock as a car with a str8 pipe exhaust. And on Supraforums someones car dynoed 340 rwhp bone stock, and the engine is only rated at 320 at the crank.