Citation Encore N486SB departed Montgomery Field (MYF) at 22:00 for a short flight to Upland (CCB). The airplane approached runway 24 for landing, above the 4-degree visual glide slope indicator. During the approach, there were two periods of sink rate warnings. About 11 seconds after the last warning the airplane touched down about 1,400 feet beyond the runway 24 displaced threshold. The published total landing length of runway 24 is 3,707 feet. Landing distance calculations revealed that the distance required for a full stop landing after touchdown was between 3,072 and 4,524 feet for the given conditions. The Citation overshot the runway and came to rest approximately 851 feet beyond the departure end. PROBABLE CAUSE: “The pilot’s unstabilized approach to the runway and failure to obtain the proper touchdown point, which resulted in a runway overrun.”