These improve efficiency and are well made.
I’m 50/50 on the look. That said, they really seem to be thoughtfully engineered. They 100% have improved efficiency likely 15%+ over the turbine replica wheel covers I had before. I believe they are more efficient than the tempest covers. If I had to guess I would say 3-5%- I changed my tires since using them so I have a confounding variable. It’s pretty binary folks reaction to them. Heck some days I love them and others not so much. They look futuristic or post futuristic - not sure. But they are high quality and I would except them to be durable as well.