Yes I agree that i-VTEC helps with gains. So yes, I agree that a K20 gains more than a B20 or a B18. But, the gains are less than what you would get for, say, a 3.5 L V8, or 2.5 L flat four, or any large displacement engine. Why? Because those engines suck in lots more air, and as a result, they are more restricted stock than Hondas are. So they stand to gain more from aftermarket intakes and exhausts. The point being, then, that displacement plays a larger role than timing.