A friendly warning to all motorists looking into buying a Mercedes Benz GL:
Many GL's, especially with 21' AMG rwheels have a hidden defect or characteristic which is not disclosed to you when buying, but which you may discover later when driving the car.
Three months ago I purchased a brand new GL350 BLUETEC. After driving less than 500 km, I discovered a vibration in the body at freeway speeds (100 - 120 km/h).
The car has been back to the dealer countless times over the last 3 months, and I have spent a huge amount of time and effort in trying to get somebody at Mercedes Benz to do something about it.
Their unashamed and comical answer is that the vibration is "normal" and caused by the road surface (on a US$110k luxury SUV with air suspension)!
For your reference, all tests were done on the N1 freeway - one of the newest, best and smoothest roads in the country.
In essence Mercedes Benz have told me to get lost, and that the case is closed as this is how the vehicle is meant to behave.
I have driven various other SUV's, including Audi Q7, Porsche Cayenne, and Lexus RX, on the very same roads and have never experienced any vibration whatsoever emanating from the roads.
Furthermore, I have discovered that this is a worldwide problem.
See this MB owner's forum, where many GL owners complain of exactly the same problem: http://mbworld.org/forums/gl-class-x166/499455-vibration-problem-new-gl550.html
If not for this abormal ride problem, otherwise an awesome vehicle.
Please be extra careful and think thrice before falling into the same consumer abuse trap.