NZAD is New Zealand Automotive Distributors. They make a big deal of telling you they get the castings factory direct; without telling you where the factory is. They're obviously chinese castings; which in and of itself is not bad. However, is it an Assault core; or a lesser quality casting? No one knows. Considering the "high performance" generic springs, and obfuscating marketing, I suspect they're a lesser quality casting.
Just my opinion.