It is not possible to get accurate kerbweights for any vehicle because these figures are so specific to each individual car, depending on its level of equipment and specification. I gather Audi is an exception here because some time ago, somebody body posted a reply in this forum that the kerbweight of each Audi car appears to be established at the end of the production line as they found a sticker somewhere in the car giving these details. However, this practice is rather an exception.
Often, approximate figures can be obtained out of the respective manufacturer's website. In the case of VW, you can download the brochure of the model you want. The Touran brochure can be found under http://www.volkswagen.co.uk/assets/pdf/touran_brochure.pdf
This shows a kerbweight of 1561kg for the manual and 1595kg for the automatic, in both cases for the 7 seater version.
The figure of 1700kg that you have also read may have been an actual figure measured when somebody took their car to a weighbridge. It is not unusual for actual figures to be considerably higher than the published ones and a difference of 100kg or even more is not unrealistic.