since you didnt answer the acronym for vtec is variable valve timing and electronic control!!it does increase the torque curve i agree but how it does it is the key i will explain for you! at roughly around 4600 rpm the hydrauilc or oil pressure builds up in the cylinder head of a vtec honda if you continue to increase throttle or completely floorboard the gas petal there are 4 pins in the top girdle of the z6 head that lock a second cam lobe in place that allows the intake and exhaust valves to be opened deeper and for a longer duration.this allows for more fuel and air to get into the motor and more exhaust to leave the motor more rapidly!! it is a big deal!! it is what put honda on the map because until vtec engages you have basically a 100h.p. motor, when you push past 4600rpm its like having a 140 plus h.p. motor so basically as i say it! if you aint talkin bout vtec you aint talkin bout shit!! thats how honda gets such great fuel economy and still power to pass cars at above 4600 rpm range!! and they doooo make power to about 9k but people have turned them to 10k!!hope this clears things up for you, and the only way i know of to make 300 h.p. plus onna D series motor is turbo! dont try to boost ur d series b7 the rods are too weak! have a nice day!