A resonator is just a glasspack with a fancy name. It's a fiberglass-packed straight-though tube with perforations in the fiberglass that slows the air down a little, deepening the tone and quieting down the sound. The increase in backpressure isn't much and they really help the sound and volume level of the exhaust system.Blu200SX said:resonator? im not familiar with that...my bad dude can you inform me?