5-speed - woohoo!
0W20 oil is factory spec. It's designed for it. Plenty of 150k+ mile Insights running around that have had nothing else in them.
You won't need lean burn instrumentation once you've driven the car a while. You'll be able to detect a difference in the throttle response, and may even feel a slight stumble entering/exiting L.B. And it's obviousl by looking at the "instant" mpg graphical display too - a ~25 MPG jump at constant load.
Or you could configure a ScanGauge with an X-Gauge to show it.