If you like the 19 inch grey ones, take a look at the Rial Lugano OE Cap in graphite silver. They were $199/wheel on Tire Rack, matched the OEM tires that came with the car, and I sold the slipstreams. They match the grey Tesla turbine wheels, so I purchased the grey caps at the service center. You may be able to get an idea from the pic in my avatar.
I get compliments on them all the time. I think the 21” turbines look great but I didn’t want all of those headaches. I am happy with the look and think they look a lot better than Tesla’s new grey slipstream.