This part does not affect the base vehicle warranty. mountune has many years of experience in engineering exhaust systems with the objective of increased power and response, coupled with an enhanced exhaust tone and appearance. The mountune Performance mk3 Focus ST cat back exhaust system is manufactured from 2.5? diameter, AISI 304 stainless steel (EN58E) mandrel-bent tubing with lazer cut flanges. All muffler assemblies are robotically TIG welded AISI 304 stainless steel for long life under extreme performance and feature consistent internal diameter throughout the entire length of the assembly. To ensure improved performance while controlling sound, each muffler includes a three-layer hybrid synthetic sound absorption packing that eliminates droning, booming, and other undesirable tones. Tubing diameter also has a major impact on sound quality and careful consideration was given to size and performance. Also incorporated are slip-fit connections at various strategic points to allow for easy installation and adjustment. Crucially, the mountune performance cat-back exhaust is the only exhaust system that will not affect your base vehicle warranty and in addition, comes with a mountune limited lifetime warranty. Features: Manufactured from AISI 304 2.5? mandrel bent stainless steel tubing TIG welded construction AISI 304 stainless steel hangers Mufflers feature consistent internal diameter 3-layer hybrid synthetic muffler packing effective to 900 degrees C Large 4? rolled edge, polished stainless steel tips with mountune logo Full width rear hanger ensures stable tip location Heavy duty “boss” type clamps CAD engineered and designed Limited lifetime warranty. This product does not affect Ford vehicle warranty.