1. Since uses OBD2 connector, does that mean I can connect to any brand/car that has OBD2 connector and read fault codes, BUT only do diagnostics part on VAG cars?
After 2008 model year, all brands around the world moved to CAN diagnostics for OBD2. You can use ' OBD2 mode on any 2008 or newer car. Older cars not so much. As already stated, if the car is compliant with the ISO9141, you may be able to use OBD2. One more point - you will not damage a interface by plugging into a non-VAG car to the best of our knowledge. Provided the connector is wired properly to the accepted international standards, the interface will power up. Whether communications can occur is another matter.
2. I would like to use with Croatian (or Slovenian or Serbian) language interface, is that possible and if it is possible would it have some drawbacks? Supposing there is an option to buy on one of mentioned languages, can I later switch to english version?
We do not have a translation into Croat or Serb. Long ago we did have one but that translation and the person doing it left. There is not enough volume of users to justify the work it takes to make a translation to Croat or Serb. You will need to use Engish or one of our other languages.
3. If I buy for instance this year (2020) would I still be able to use it in the future on, e.g. cars made in year 2022, better say will RossTech still provide me with databases for those new cars in future?
As we now are celebrating our 20th anniversary, we still have users from our first year in business who have enjoyed free updates to their VAG-COM and in all of those 20 years. We guarantee free updates for one year from the date of purchase. In our 20 year history, we have never charged any party for updates to the software. Now, given life, we cannot know if we will be able to continue to do so forever. A day may come when economic reality causes us to change our operating methods. As long as we meet our 1 year commitment to users, we feel we are within our right to change.
That's software... hardware - the interface itself is another matter. Any day, VAG could come along and change things in the way they connect to external hardware. Or, they could change things within the cars rendering our sophisticated electronics in our interface unable to support as happened in 2016. VAG changed the addressing scheme within the cars and we simply had no room left in the device to accommodate the changes they made. We had no choice - new interfaces had to be designed.
We think we are ahead of the curve. That said, VAG has 2 protocols they are playing with and which are now showing up in cars.. Still they are doing all diagnostics via the methods used in the past - CAN/ and so on. But why are they putting new hardware protocols in the car and why are these wired to the Data Link Connector (DLC/OBD2 connector)? We are working on new designs that will include one of these.. Will that mean that some will have to buy new hardware? Probably some day in the near future - yes.
VAG checks nothing with us. We do it all by reverse engineering. We cannot know in advance what VAG has on the horizon. We can only respond when we see new things arriving in the vehicles for sale.
There is no means by which we can future proof your purchase beyond what we have done. Change is the only constant in this universe.