I had a 2.25 dual system on my '09 2.5i Impreza with AP Exhaust Xlerator mufflers. The center tube was cut just behind the gearbox, removing the factory resonator. Not only was the system loud, but it made that hoarse farting sound that I really don't like. After installing this resonator, the exhaust became quieter, not quieter. Sounds great, the rattle is gone and nothing is left but a nice deep sound at low revs, but still loud enough at high revs. The drone has also retreated from highwayβ¦