I've had my W221 2008 S320 for almost a year now and over the past few months I've noticed a harsher and firm ride. I can feel all the bumps in the road and it feels like the dampening/absorbing components are not doing their job. When I go over bumps slowly, I can hear a sound, its hard to describe, but its creeky. I've been paying close attention lately so that I can give as much info to the mechanic to diagnose the faulty component(s). Here's what I've done so far: 1) after seeing rave reviews, I gave the car for a major service to Waynes Gates of Harrow. I mentioned the harsh ride and Terry drove it and agreed it was hard/harsh. But he couldn't find any obvious problems. As my tyres were almost finished, he advised me to get them changed first. 2) got Michelin Primacy HP's MO all round. Gave the wheels to BVJ to be refurbed - didn't want any bent alloys causing problems. BVJ reported no structural problems with the wheels. So far so good. Since then, the ride has been improved but the hardness is still apparent. 3) after reading these forums, I revved the car to 3-4k whilst in Parked mode with Parking brake on - no car shake was felt. 4) I've been observing the car's height, something I've never even been aware of. Sometimes the rear (both left and right) would sink overnight or after some length of time. Indeed, sometimes, it stays in the "lower" position even after driving. What is the expected gap between tyre and the wheel arch? I have nothing to benchmark it against, but today, I'd say the fronts had 80-85mm gap and the rear arches had 60mm gap - would you say this is normal? 5) when I raise the car (pressing the button in the dash) the car raises itself by around 25-30mm all around. "Vehicle Rising" can be seen on the display. After measuring again, all four corners have risen by approx. 25mm. I pressed the off button but nothing happened (perhaps I didn't wait long enough). I turned off the ignition and removed key, shortly, the car lowered itself to its "normal" height, all round. Again, the rear had a 60mm height between tyre and arch, the fronts still around 80-85mm. What else can I try to isolate the problem? Bouncing the corners perhaps? I intend to give the car to Terry (Wayes Gates) to take a look, but the more info I can provide the better. Any ideas on what it could be and how to resolve it?