Has anyone used these? It looks like the big turbo supra's have had good luck with them. Any thoughts?

 

Would like to know this also

 

This has been discussed before, but as far as I know nobody has actually tried the SP QSV specifically. Basically the discussion boils down to the fact that Mazda already tried this on the S4 TIIs, and ditched it for a fully divided manifold on the S5 TIIs. I don't think you would see improvement over a proper fully divided setup for a 2 rotor.