Not true. There may be a lot of sheet metal manifolds on the market based off of this design, but they are not always on par with the quality. Golden Eagle manifolds are made with higher quality materials, and the welds are better. Some of the more mass produced versions, such as the HP Racing version that I used to have, look identical, but are not 100% identical, as I learned when I had to get mine partially re-welded... Thus the reason some are $600, and some are $300....