Cold Air Intake For Honda Civic Si (2006-2011) with 2.0L L4 Engine RedHigh Velocity Induction: K20Z3 Thermal Optimization Who Its For: Engineered for 8th Generation Honda Civic Si owners running the high revving K20Z3 powerplant who are tired of the stock sluggishness and muffled engine note. The Symptom: The factory intake on the K20Z3 engine is a maze of plastic baffles and restrictive resonator boxes designed for silence, not velocity. This labyrinthine path creates significant air turbulence and heat soak,