I think far too many people get it wrong when trying to increase air flow without having a good understanding of airflow principles and an airflow bench at their disposal. Larger is not always better!! A better approach is to cleanup the airflow by polishing, making any bends less angular, making them equal, etc. If you enlarge everything, you increase the potential max airflow but you may have decreased the actual flow due to decreased velocity. You also have to be concerned with your exhaust. You can't get more in if you can't get it out. These engines were designed and built by experts (AMG) so don't expect a huge gain without modifications of the entire system; more air means more fuel, a larger capacity pump, maybe larger injectors, etc. Read what others have done, take it in small steps. If one mod, on it's own can net +20 hp and another mod can net + 25 hp, that does not mean together they will net + 45 hp. It might be more like 35 combined.