What is the difference between MACE PERFORMANCE CPR6 INTAKE MANIFOLD FOR HOLDEN CALAIS VE ALLOYTEC LY7 3.6L V6 and the stock manifold?

CPR6 manifold is made from high-quality automotive-grade cast alloy, the CPR6 boasts far greater breathing and airflow characteristics than the factory product. It provides the Alloytec V6 with more air and a cleaner intake path, you'll see power gains of 11%. You will lose a little power low end but when the revs go up a little it will be so much easier to breathe.