Torque Solution Titanium Axle Back Exhaust Where's My Package UPS United States. Torque Solution Titanium Axle Back Exhaust for Subaru WRX and STI The Torque Solution titanium axle back exhaust system is designed to enhance both performance and sound for Subaru WRX 2015 to 2025 and STI 2015 to 2021 models. Built from precision welded pie cut titanium tubing measuring 2. 5" in diameter, this lightweight system offers a crisp, aggressive tone while reducing mass compared to the factory mufflers. Each side weighs only 1. 2 kg, providing a total system weight of 2. 4 kg and a reduction of roughly 9. 5 to 10. 0 kg when compared with the bulky OEM units. The system is compatible with the factory mid pipe as well as direct fit aftermarket mid pipes, making installation straightforward. The burnt titanium tips are fully adjustable, allowing you to fine tune their position within the bumper opening. Finished in blue and purple with the Torque Solution logo, they deliver a premium motorsport look to match the sound.