Diesel do you have a 2012 focus? Other cars may sound different with out the rear main muffler. The reason this works is because the 12's have two mufflers and a resonator.
'14 Fiesta ST
200HP / 263 TQ
SCT Tune & Injen Intake
Moderator: Third Generation Ford Focus, DURATEC Ti-VCT GDI Performance Chat & Florida regional section