For those of you who purchased a BORLA® "S-Type" system, PN 140791 or 140791BC and want to step it up to the ATAK® sound, replace the front resonators with this set. Each resonator is built from premium T-304 stainless steel, superior to T-400 series knockoffs (such as 409) to give you the best in performance and duarbility. Ultra-smooth mandrel bends ensure maximum flow & power, and precision computer numerical control (CNC) manufacturing ensures an accurate fit. As with all Borla® products, it is covered by the famous Million Mile Warranty.