i've always followed the vehicle manufacturer's suggestion for tire pressure, and used the sidewall max pressure value only to ensure it's not lower than what's inside the fuel filler door (or door jamb).
now i'm reading many suggestions @ fred's tdi forum about ignoring what's written on the car and going with 80-85% of the max printed on the sidewall. seem some are even exceeding that.
sounds crazy to me, but i'm willing to be edumacated.
fwiw, my current (winter) tires are Dunlop Winter Sport 3D (max pressure 50 psi) and my other set (all-season) are Goodyear Eagle RSA (max pressure 51 psi). i usually run 30-32 psi, based on what's written on the car.
am i being too conservative? is there a world of better handling and mileage awaiting me?