Why this made the Sone list? 417 Motorsports, based out of Springfield, Missouri. Designed, engineered, and handcrafted in the USA.  If you had access to the best precision welding and software available, this is what the perfect set of bypass pipes would look like. 

This is true engineering. Built for precision, power, and long term reliability, these catless downpipes are the only ones on the market featuring fully CNC machined flanges. That means superior sealing, maximum durability, and perfect alignment every time.

Constructed from premium 304 stainless steel, each unit is precision TIG welded and jig built to ensure consistent, accurate fitment on every install. An integrated O2 sensor extension helps prevent check engine lights, and the design retains all factory heat shielding for proper thermal management.

The result:

A deeper, more aggressive exhaust note
Noticeable horsepower and torque gains
A flawless OEM plus fit and finish

These downpipes deliver the sound, performance, and quality your 991.2 deserves. Built with craftsmanship you can see and performance you can feel.