Quick view Borla Borla 2019 Chevrolet Silverado/Sierra 1500 6.2L Atak 3.5in Diameter Polyphonic Harmonizer - 60680 Compare $236.99 $211.99 Replace the small muffler behind the primary muffler in the BORLA? "S-Type" system with Polyphonic Harmonizer 60680 to attain the "ATAK?" sound level (louder than "S-Type"). BORLA?'S Polyphonic Harmonizer Technology utilizes patented units that contain... Add to Cart Add to Cart