I read an article once that put the Mugen header on the top for HP gains when tested against all of the other brands. These gains were all made in the very upper end of the powerband though and the car actually lost some of that "all important street driving" low and mid-range. Header choice needs to be made based on driving style. If you are going to be on the track all day, the Mugen (although the most expensive should not have been over $1000) might be the way to go. The rest of us that drive in the real world would probably be better with something else. Love my DC. 
