I have a 2007 Lexus IS 250 with 58k miles that I bought recently, runs great.
The oil cap and manual specify 5w-30 oil, but there was 5w-20 oil in the car when I bought it. It turns out Toyota put out a service bulletin for this engine changing the recommendation to 5w20, they claim it's better for MPG and cold start protection.
I read online that this was a move to boost MPG at the cost of the better engine protection of 5w-30.
I live in NC. Which would you use if you cared more about engine life than MPG?