I've been asked for a sound clip from my 2017 Corolla iM after I installed my DC Sports CAI and ceramic header along with the DNA exhaust. I'm very pleased with the sound and opening up the exhaust and intake have injected some much desired power and responsiveness. For those that say these mods don't help haven't done them together. I also have upgraded the VVT-i solenoids with the Quantum Solenoids. The combination of these mods is fantastic in the results.