I have an 06 cs. I was wondering how difficult/it is even possible to add the air suspension form the turbo models onto my car.

I know many of you will say just 'just upgrade to a turbo' but i have a lot of money into this car already.

 

obviously the answer is yes...you can do anything if you have enough money/time and the correct parts.
logistically i would say no...as it would involve changing not only the "air suspension" units, but the larger wishbones there mounted onto (and any things that are connected to them)
then you have the ECU air module that controls the ride height when going over a certain speed, then there is the switch gear by the 4 wheel select leaver, and the sport/normal/comfort leaver.
then you would have to get it all programed, and linked together.

the only way i could see a "swap over" working is if you bought a wreck and took off all the bits you needed, other wise it would work out so expensive.
but if you drive a cayenne with air suspension you would see in a heart beat that it is sooo worth it.

good luck.