The best manifold you can buy for your C15. A beautifully crafted CNC billet steel masterpiece! Far superior performance than any other product. EGTs were 150 degrees lower than even the best aftermarket manifold while spooling the turbo faster with higher peak boost and 6 lbs less drive pressure. This manifold is one piece so will never leak and is easy on studs and gaskets. In normal service it shouldn’t need to be retorqued either. Expect long service life and the best fuel economy ever from this manifold.