Borla 23-24 Nissan Z 2.5in S-Type Cat Back Exhaust 4.5in Tip - Stainless Steel TipsBorla 23 24 Nissan Z 2. 5in S Type Cat Back Exhaust 4. 5in Tip Stainless Steel Tips This system is a True Dual design that features a Merge X Pipe and Polyphonic harmonizer technolgy. All of these features combine to provide the classic S Type sound level and the BORLA no drone guarantee. The Merge X Pipe blends the combustion pulses from both sides of the engine for improved performance and a custom sound. BORLA'S Polyphonic Harmonizer Technology