I personally like to run a higher pressure in the back than in the front, about a 4-6 psi difference to make the car oversteer a bit more than it's supposed to, this is not good for tire life though

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2006 BMW X5 4.8is Lemans Blue/Beige/Dark Maple
-Nav, Comfort Seats, Heated Steering Wheel,
Rear Airbags, AUX Input
2009 BMW M3 Space Grey/Black/Carbon
-all options