of a cork membrane is it absorbs any flaws in either the marble or the dryvit (the floor in the condo is actually a concrete dirivative called dryvit) and will help the marble stay intact.
Remember that marble is VERY HEAVY and may affect the structural loading of the building. Also, remember door clearances, dishwasher clearances, stoves, etc. Make sure you don't tile your dishwasher into a PERMANENT Location!!!!!
Have your installer check all of the marble before he begins installation. Marble is a natural product and color can vary from box to box. You want the color variations to be mixed and blended.
Lastly, when I did this for a customer last spring, we left the existing base moulding in place, then installed a small base shoe to fill in the gap between the marble and the original base. The result was beautiful!