Thanks everyone! I really like the plain silver look that (almost) matches the car's paint. This week is pretty busy for me so I won't have time to do a real controlled test. A few things I have learned so far: Aluminium is a very soft metal. Very easy to drill and machine, but too soft for a thread that is used a lot. The friction of just putting the screws in and out wears the thread out. I have two possible solutions for this, but that's further down the line. The disks vibrate a little and create some noise. Not bad, but if you turn off AC and music you can sometimes hear it a little. Mostly because they are attached on the outside while the center is loose. Easy to fix, but again, not a priority right now for me. I think the flat shape is the worst when it comes to vibration, too. Each time you want to check the tire pressure you have to take them off. Drilling a big enough hole in them to reach through to the valve would fix it. Not sure I want to. My goal is to show there is hopefully enough of a benefit of having closed wheels that either Tesla or a different manufacturer starts making a real aero rim that is closed and smooth. Not a fake one that still has holes and pretends to look like a normal rim. If anyone knows a company that is willing to custom machine rims, let me know.