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Subaru WRX STI (2015–2021) Exhaust FAQ's

Please read our FAQs page to find out more.

What exhaust layout works best for a daily‑driven but track‑curious STI?

A resonated cat‑back balances comfort and flow. Pair with a region‑appropriate front pipe solution to keep the cabin civil while improving mid‑range response.

Will a larger‑diameter STI system drone on the highway?

Quality resonators, Helmholtz chambers, and proper muffler design tame low‑RPM resonance. Choose systems known for good NVH control on the VA chassis.

Do I need tuning after exhaust changes on the STI?

Cat‑back only typically doesn’t. Significant pre‑cat or turbo‑adjacent changes may require calibration for trims, boost control, and knock margin.