The main part for the high output is the exhaust manifold shown on the right graph.
We recommend having a total full straight exhaust tuning by having more power by changing the muffler and exhaust manifold and tune the sound with the front pipe.
* If the exhaust manifold is changed, the engine check light might be turn on for a certain combination. So the muffler + front pipe combination is an effective choice.
HKS: SS F/Pipe Toyota 86/Subaru BRZ (CAT less off road use only)
Brand: HKS
Part Number: 33004-BT002
Stock images used. Actual product may vary.