Boost your 2017 to 2019 Civic Si's performance with the New Drop-In Turbocharger Upgrade, model 49S31-A0100, from MITSUBISHI. This TD03LL1-04*11HR2-5.1 model turbocharger is ideal for enhancing engine power and efficiency. It includes a 1-year manufacturer's warranty. Note: Ensure proper engine oil use to avoid issues like noise or damage. Cross-reference numbers include 49131-A0100 and 49995-11701.