Q: Is the Model S Plaid brake upgrade worth it for street and occasional track?

For a Plaid or Long Range driven hard, yes. The factory brakes are fine for casual use, but decelerating nearly 5,000 lbs from triple-digit speeds over and over generates enormous heat, and stock hardware runs out of thermal room during back-to-back launches and repeated hard stops on a mountain road or a track. Stage 2 is built to push those limits far out while staying quiet and comfortable in daily driving. It is the sweet spot for owners who want serious capability without going full race build.