 (Previously leased 2003 4.4 and 2008 4.8 X5 models).By far, this 50i model is my favorite X5.Improved satellite navigation system lets you speak the entire destination at once, instead of bit-by-bit, and is usually accurate.Sound system has both an equalizer and surround sound.Excellent back-up camera that shows not only the rear view, but also view from above, which is great for back-in and parallel parking.8-speed automatic is noticeably smoother than the earlier X5's 6-speeds transmissions.Fuel economy is slightly better than the earlier X5's (averaging 13.5 to 15.0 MPG).The 19" tires help.The '03 and '08 X5's both had 20" tires (and were more expensive to replace).