The ZZPerformance catback system is the best exhaust money can buy for the LS4 Grand Prix. Constructed of stainless tubing and flanges, the ZZPerformance 2.5" exhaust system will last virtually forever. This also comes with ZZP's exclusive stainless chambered resonator and mufflers.Can be optioned with the ZZP resonator or without. We highly recommend the resonator for all setups.  Mandrel bent polished stainless tubing Stainless welds Custom Y transitions smoothly from 2.5" to dual 2.25" Double wall polished stainless tips Polished stainless mufflers Stainless resonator Hangers in all OEM locations Includes all required clamps and gasket Direct bolt in Stainless: Unlike mild steel systems like the Pacesetter, which has an expected life of 2 years in northern states, this exhaust system has been built with no compromises. Shipping weight due to being over-sized. UPS shipping only. Does not fix LS4 Monte Carlo SS