Took a chance buying a used 2003 X5 4.6 with over 80,000 miles. Have put around 3,000 miles on it so far. Not a commuter car. Best as a hot rod Sunday driver or to the lake towing 2 wave runners or a boat. Horrible radio. You'll want to totally replace the radio 'head unit' so factor in about $1,000 for that if you DIY. Very nice seats. Fit and finish for 2003 exceptional. Ride too harsh for most people, but lower tire pressure will help. One thing critics overlook is that this machine was built to tow 6,000 pounds! So much power. Quick at 0-60 in 6.5. More than you will ever use. Could you take this car to 300K? Maybe, if you are gentle. But prepare to pay the $. It's really a 2nd car.
Plush seats. Muscular look. Big wheels/tires on the 4.6. Looks like a Hot Wheelz car. 6,000 lb towing capacity. Head turner. Still looks better than many newer generation SUVs. Cornering is awesome. Quickness is shocking for an SUV, especially of this era.
Replace radio head unit. Lower tire pressure for softer ride. Might want to wear gloves as steering wheels feels slippery. Watch out for big wheels/tires of the 4.6 as they can get caught in rain ruts made from smaller wheels on the freeway and jerk you around. Best if you DIY repair on most items or find a good independent shop. Dealer repair too expensive.