I realize that with the MB's it is hit or miss on airflow. Poorly designed headers are going to lose power on the engine vs. the gain we all want. I am a little impatient as it has been awhile since there was an update and I would like to add some power (right now I prefer to add power without going to an ECU/Pulley solution). If I was near LA I know of an outstanding shop that makes custom headers. Unfortunately they are a bit far.