We ran both sprays on the same M3 Competition simultaneously — HydroSpeed on the driver side, HydroCharge Plus on the passenger side. Same application method, same wash schedule, same parking conditions. At six weeks HydroSpeed was still sheeting water cleanly. HydroCharge showed early degradation in the bead pattern. At eight weeks HydroSpeed was the clear winner. The four-dollar price difference doesn't explain the performance gap but HydroSpeed is still the right call.