Bolt on the best sound available for your 2005-09 Mustang GT with Borla's ATAK Axle Back exhaust system! Borla has taken the time to research and design a vehicle specific sound with the control over the acoustical note of the exhaust throughout the RPM range. Borla's patented multicore design, called ATAK (Acoustically-Tuned Applied Kinetics), produces the highest available decibel levels in their street series lineup. The main focus is to get the highest volume while retaining clarity of sound and avoiding obnoxious distortion found in other Axle Back kits. Borla compares this to a musicians graphic equalizer and when you hear it you'll agree. All of this is acquired without sacrificing performance.