when you say 4.6, I'm assuming you're looking at an 03 model? Beginning in 2004, the 4.6is was replaced with the 4.8is. The "is" models offer things standard that are optional on the 4.4i. Servotronic, premium sound, n/c comfort seats, nappa leather, stronger engine, bigger brakes, sport suspension, and a plethora of items I haven't mentioned. If you're looking for a loaded 4.4, I'd recommend looking for a 4.6. There's definitely a difference that you'll notice if you drive both. As for the 4.8, adjustable ride height became standard, another cool option so entry/exit from the X5 is easier ... Good luck!!!!

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