From the launch; found this quote from MotorTrend "
The Performance Upgrade Package is a no-cost option that lowers the suspension, adds 21-inch wheels and summer tires, and performance brakes and increases top speed to 155 mph (note: Tesla acknowledges that the PUP reduces range from 315 to 280 but does not provide revised EPA numbers for this package)."
Tesla Model Y Long Range vs. Performance: Which Electric SUV Is the Better Buy?
Here is a page that shows that the ground clearance of the Performance Model Y is 5.51".
Tesla Model Y Performance AWD Technical Specs, Dimensions
When the Performance Model Y was initially released you could select the performance upgrade package (PUP) at no extra charge or stay with the standard Model Y wheels, suspension and brakes. The ground clearance only lowered if you have the PUP; now all Performance Model Y include the PUP.
My recollection is that the difference was 0.5" lower; now I think the Performance Model Y with PUP may actually be ~1 inch lower than the ground clearance of the Long Range Model Y (6.6").