I installed
Air Tabs last fall. After driving 4,000 miles in different weather conditions. I find they make a difference. Less pull from passing trucks. Less side wind movement. As far a mileage. I have not seen any. But I had to run in some high head on winds that sucked any MPG improvements that could have been seen. Keeping rear window and toad clean. Does seem to have made some improvement. Heading south to TX last December we ran in wet salt covered roads. Next day we drove in rain all day. When we got to our destination in TX. There was not the usual thick cover of road salt and dirt on toad.
Just for the handling improvements I like them. Not sure that I would pay the going price of $220 for a set of 80. Got 90 of them off EBAY for $100.