Depends on which model you have and the options on the vehicle.
Case in point - Australia got the 7P series with air suspension and North America did not. Ross Tech can't assist on matters to do with air suspension on this series, rather only "best guess" what might be going on. I will defend Ross Tech here quite stringently though because in the absence of having a vehicle to work with to ensure the software was sending the right code to the vehicle, they've had to assume certain parameters / information, and it isn't quite right - close but not right.
When you go into adaptations in the module for the air suspension, it looks totally different to anything you can find on the web and trying to adjust the suspension is truly a hit and miss affair.
The measurements that come up don't equate to what the actual measurements are on the vehicle. Putting in changes can result in the car going up or down a large amount and/or even adjusting in the wrong direction (eg putting in a higher measurement should lower the suspension but it goes up and vica versa). That's when you start to really crap your daks that you're not going to get it working again.
The mechanical faults that come up have hysterically different mileage readings compared to actual, and in one case we saw a date of the 26th month 2016. And we double checked, it wasn't the 26th day of a month, it was the 26th month... Oh, and there's the whole 2016 thing too....
It then becomes a game of chance as to what the suspension will or won't do until the compressor overheats and you have to wait several hours and pick up where you left off. In all it took us approx 6 hours of actual log time to get a minor change correct.
Conversely,
@Window wizard has shown a tool which I have seen a video demonstration of working perfectly well with a Cayenne of similar vintage to the 7P Touareg. Ok, it's not a Touareg but I strongly doubt the language is different between the 2 vehicles of the same year with the same suspension, and how the unit worked with data input seemed very straight forward.
In all, I don't know how good (or not) the Icarsoft unit is overall but to just say "get the VCDS" without knowing what the Icarsoft can do, or what model of Touareg the OP has, or what he wants to do/change is not sound advice.
I would suggest contacting the supplier for a demonstration on the vehicle itself and decide from there if it's worthwhile...
Just my $0.02.
Oz