Intake manifold. Copied Elddebrock performer RPM.

I'd still love to know if there are differences between the different ones marketed.
They could all be from the same casting foundry...or they could be different.
Hard to tell with all the fly by night MFG that goes on in China.
I'd like to know if any of the offerings are better than others.
Especially since there's such a wide range in experiences from "they suck" to "they're great".