Hi can anyone advise of a possible refurb rear suspension bag for my S211 T model 2003 E270 as new ones are not worth it for the car?

The car is usually sitting just above the alloy on the O/S when parked (Although some days its fine and sits at normal height), but when the car is turned on then after a few minutes the vehicle raises to normal height without any issues whilst driving.

Plus I don't know the part numbers for the suspension fitted to my car.

Is it Airmatic W/O Code 489 (What ever the code means) or with the code etc.

Any help on the matter is greatly appreciated