HKS Hi-Power Muffler WRX STI/WRX 2015 US

The 75mm piping diameter on this HKS Hi-Power muffler is a key design choice for the 2015 Subaru WRX and WRX STI. This larger diameter allows exhaust gases to flow more freely compared to the stock system, which can make a notable difference in how the engine breathes. The muffler itself features a 120mm tip, giving the rear of the car a more aggressive look that matches the improved exhaust note.

HKS has a long history with performance exhaust systems, and this Hi-Power muffler is built with that experience in mind. The construction uses durable materials designed to withstand the heat and vibrations typical of a performance exhaust. While it's a cat-back system, meaning it replaces the exhaust from the catalytic converter back, it's designed to integrate with your existing setup. The goal is to provide a more satisfying exhaust sound and potentially improved throttle response without requiring extensive modifications.

When installing a cat-back system like this, you'll typically find it's a bolt-on affair, but it's always a good idea to have a helper and ensure you have the right tools on hand. The improved exhaust flow can also complement other engine modifications, should you decide to go further down that road. This muffler aims to provide a balance between a sportier sound and a well-built component that can handle the demands of your WRX or STI.