Always stick to the car manufacturer's recommended inflation pressures - don't use the MAX values on the tire. On my '92 300SE, the values are inside the fuel cap door.

This is assuming that your tires are the same size as the factory specifications - MB knows what pressures will give the best combination of tire wear, ride quality and performance.

44PSI will find you in short order with 4 tires with great tread at the edges and bald in the middle - then you'll be stuck with buying new tires PLUS the cost of getting all of the fillings in your teeth re-glued after being rattled loose by those rock-hard tires.

All this being said, I don't follow the MB recommended pressures to the letter - they say 27frt and 30 rear - I find 27 makes the car too "loose" - so I run 30. So far, so good.