RE: Can you change the air suspension from a V-Class to Spring suspension?
I don't beleive there are any aftermarket suppliers for this. If you REALLY feel a need to do this, go to the dealership, have them connect the diagnostic computer and then they can reset the baseline of suspension height. You will most likely have to sign a waiver of some sort and this may also void part of your warranty.
I suggest that you ask the mechanic to replace the whole system (Spring , Absorber and Lower Arm Struts) with the one use in MB VITO model. Vito use Spring Suspension.
It is Quite expensive and the ride is hard but less headache...most V-Class owner in Malaysia convert them to Spring. However i still use Air suspension for it's smooth ride.