Q: How do I choose between the 19, 20, and 21 inch sets?

Pick by ride and looks. The 19-inch set gives more sidewall for a compliant ride and pothole resistance; the 21-inch set fills the arch and looks the most aggressive, with the firmest ride. The wheel accepts the standard factory 21-inch Model S tire and 19-inch Model 3 tire, so you can often carry over factory-sized rubber. If your car is specifically a Model S Plaid, the Model S Plaid carbon fiber listing covers the same wheel.