this looks to good to be true, has it been proven?

[Tachyon]

They work well.

Here's a dyno of a 16g gas setup from 2007:



Blue line is the Cyclone, red is a 1G Stock manifold.


The record for max power on a Cyclone was 621 HP on a DJ using a laggy GT-35:



I suspect like scheides said, it would be a restriction on high-flow setups, but I have absolute data from back-to-back runs with the same setup.