Drifts N' Lifts tested one of their 1JZ cast exhaust manifolds against a custom tubular exhaust manifold. Link to the video here: https://www.youtube.com/watch?v=fhFN5qqKnT8&t=323s&ab_channel=DriftsN%27Lifts
Kangaroo Racing reached out to the Volvo community late January (TurboBricks) to get some information about what would be the best platform and design for a cast iron manifold. Link to the thread here: https://www.facebook.com/groups/2204727570/permalink/10162745202337571/
I can't see any reason to believe they are a scam, I am genuinely interested to see how they perform with the B230 platform. It would be great to have something with the durability of cast iron as an option moving forward, especially since I myself am looking to replace the pre 90's hair blower of an exhaust manifold in the near future.
Hope these links help.