Actually there are a few type's of VTEC. Most cars have VTEC for gas mileage and a little better power this version comes on civics, accords, pretty much any SOHC engine thats VTEC. Then you have VTEC-E not to be confused with i-VTEC, this can be found on the civic HX it basically keeps an intake valve closed at all times during lower RPMs to create a swirl effect in the chamber allowing the engine to run lean (lean means more power but more heat). Then you have the "real VTEC" this can be found on Integra's, Preludes, NSXs, and Civic Si's. These engines use VTEC primarily for performance purposes. These engine are DOHC engines. This form of VTEC allows decent low end torque and screaming upper RPM power, by allow valve overlap once the secondary cab lobes are activated.