@JimN said, in part: The bottoms are a bit of a PITA to remove & replace so the only time they come off is when I really want to wash & wax the car thoroughly. Are you using zip ties? I've found two-sided velcro tape good for this. Very easy to install/remove. I get this stuff at Lee Valley Tools, up here. It's an American product though:
I'm pleased to report an increase of 10mpg by making the following changes: Removal of bike roof rack (likely the largest factor) Repair of leaking front, passenger side tire Installation of foam grill block (upper and lower) Some changes to my driving technique (no longer forcing EV) Leaving climate control off until I'm on the highway, allowing the ICE to warm up during the initial 5 miles of driving These changes have improved my mpg from around 34 to 44, and the improvements are still coming with this tank of fuel! Thanks all. This is great! I think I'll install a block heater to see what that does.
No, I'm too cheap to buy velcro tape. I am recycling twist ties. If only Frost King had bundled velcro tape with their pipe insulation...