Awhile ago I purchased a Pro Chamber from a friend for my Cobra. However, I didn't realize that when bought new there is a reducer that goes inbetween the driver's side manifold and the Pro Chamber itself to prevent leaks. Well after replacing an O2 sensor and tightening the bolts as much as I could I still had a leak and a check engine light to go with it. Which brings us to today. I just called MAC and told them about my situation and they said they would ship the reducer to me free of charge, I just have to cover shipping!!!! So once it arrives I'll finally be able to get rid of my leak and my check engine light for good. Two :thumbsup: for MAC customer service. :beer: