The exhaust manifold of 86/BRZ is very important for higher power. Stock exhaust manifold has a catalyzer and it's causing a resistance for exhaust output that make the engine to perform poorly. HKS SUPER MANIFOLD with CATALYZER GT-SPEC for ZN6/ZC6 uses a compact and high cleaning capacity catalyzer, still it has a low resistance which passes Japan Exhaust Gas Regulation. It's a high and efficient performance manifold for your 86/BRZ.
HKS: Manifold GT Spec with Catalyser 86/BRZ (MT only!)
Brand: HKS
Part Number: 33005-AT007
Stock images used. Actual product may vary.