Hi Dan, I'm pleased to assist you. Yes, a resonator is needed in an exhaust system as it helps to reduce noise and improve exhaust flow. A resonator primarily affects sound, not power. Removing it might result in a slightly louder, more aggressive exhaust, but it won't significantly increase horsepower or torque. While uncommon, some factory exhaust systems rely on the resonator for proper emissions control. Removing the resonator could potentially affect emission test results. If you're interested in this resonator, use this link to continue ordering before the sale ends. I hope this helps and enjoy shopping! https://www.carparts.com/resonator/brexhaust/bo1026538?can=CPGG4850_CSQA_20240129