Finnish TV show Puskuri compares 1985 Chevrolet Corvette, 1991 Toyota Supra and 1981 Porsche 928. All three with automatic gearbox and are similarly priced in Finnish used car market.
Porsche 928 PSD differential operation explained in marketing video. System was standard equipment on S4, GT and GTS models made between 1990 and 1995 model years. It can vary locking amount between 0 and 100% according to needs of driving conditions. System utilizes ABS sensors and accelerometer to determine correct actions for stabilizing cars behaviour.