Emphasizing Torque at Low/Medium Speeds,
Sound Volume and Quality Fit Street Use
And Stylish End-pipe will Dress Up Your Car

When you step the accelerator more strongly than usual, the exhaust sound begins to assert itself. You will feel the Prodrive spirit. Hopefully, you will be satisfied with the well-tempered, not unduly stimulating, sounds.
This exhaust system for Legacy Touring Wagon BP5, born out of the Prodrive's philosophy, is tuned for street use, emphasizing torque at low and medium speeds. It is rear piece only, made of SUS304 stainless. The pipe diameter is 54mm at the rear piece and 115mm at the tail end, on which the Prodrive logo is engraved. And the newly added model for BL5 Legacy B4 is designed for the sedan body, retaining the basic specifications of the existing model.

https://www.prodrive-japan.com/en/products/muffler/ex_lega_bp5bl5.html