SUPER MANIFOLD W/ CATA R-SPEC ZN6/ZC633005 AT006 SUPER MANIFOLD with CATALYZER R SPEC is more advanced and upgraded product of SUPER MANIFOLD with CATALYZER GT SPEC. By removal of the catalyzer at the exhaust manifold, we could have a substantial reduction of the exhaust pressure. We also redesigned layout of front pipe with HKS metal catalyzer (this product comes with front pipe that passed Japan exhaust regulation). * Only used with stock muffler will be compliant for Japanese safety