i am driving a camry 2.4L vvt i engine. I always use castrol magnatec 10w-40. its pretty good oil protects engine as well. last time, I serviced my car from toyota dealer, they also used mobil Super 10w-40 motor oil. "5w-30, 10w-30, or 10w -40 are all just oil viscosity that for "temperature range anticipated before next oil change" you could even use 20w-50 cheapest motor oil for your vvt-i engine without a problem. car engines are not that sensentive. as long as you have correct level of engine oil, you can will run good. regardless of what oil you actually use by the way, Owners manual is written by toyota, of course toyota wants you to buy all parts from dealers. anyway, I never believe about genuine parts except the toyota super long life coolant, which i couldn't get from anywhere else.