I got a set of the magnetic ones and put them on my car (Mazda CX-5) right in front of the rear spoiler. My normal highway commute is usually 28-29 mpg. I’ve been seeing 30-31 mpg with the pods. I wonder if it would be better if the pods were on top of the rear spoiler itself, and what the effect of spoiler vs no spoiler is on mileage. It’s a lease, so no big modifications for me.