We have a 2008 Mini Cooper base model with automatic and it now has 20,000 miles. During the free maintenance program we had to use the Mini Synthetic 5w30. We live in Eastern Kansas where it sometimes gets cold but also can get over 100 in the summer. All it is used for is driving to work about 5 miles a trip or short hops around town. Now that we're beyond free maintenance, I want to use Redline but can't decide whether to go with 0w30 or 5w30. I want to increase the gas mileage if possible but am concerned about the 0-30 not meeting A3/B3. I have read some posts of people getting better mileage with the 0w30 of other brands of oil. Any thoughts anyone?