I will start the car and let it run for a bit every week, but that will be in the garage. Not going onto the salted roads. The driving I want to do isn't really winter driving.
Opposite directions on two 5 hour drives with shop time inbetween... and I'm guessing wind speeds/temperature/road incline were all different over those two separate 5 hour drives. Every little change matters.
Look, if you feel like it's helped, great. Feel free to continue having that feeling...
Because any number of things make more sense to attribute the difference in gas mileage to than the oil type. (change in weather, direction of travel, etc).
Causation vs Correlation analysis going on.
Just my 2 cents, I wouldn't buy a $100K car that I'm unsure if I like it. So few Emiras will be sent to the US, let someone who loves it be the first owner. If it's 50/50 between these two cars, I'm not convinced you will actually like this kind of car.
He's an "old Lotus" fanboi. Which to me, means he'd have the most reason to be MORE critical of a heavier car, with lots of extras. The fact that he likes it and identifies it as being uniquely Lotus is quite the compliment for the car.
My car has red interior and sports suspension, but otherwise looks exactly the same. I love it and have been very happy. Congrats on yours and hope you love it just as much.