I love it when those without sufficient knowledge ask for advice\opinions and then not only disregard them, but they actually tell those who are trying to help them how it really is..... if you already know better than the rest of us, you shouldn't be asking.
Now, read carefully what I typed.
Since you're not providing specific details or links to a specific product, I will have to just give you an example of one that I know of.....
As said in my initial post, the existing system on a trailer is very simple.
Notice how this "piggy back" system, needs to be wired to the individual trailer axles\wheels to allow it the ability to individually brake specific wheels.
Pay attention to the system description which also tells you that the system includes all kinds of sensors and microprocessors.......
Notice how this system DOES NOT feed back into the vehicle stability control (or whatever it is called on each specific tow vehicle), but it works in CONJUNCTION with it...... remember that 7pin connector with only ONE BLUE BRAKE WIRE...... you can't have all this back and forth communication with the Touareg's ECU for it to try to attempt to sort out what's happening with the trailer and to send individual signals and brake\correction instructions to individual trailer wheels using this SINGLE WIRE.... it can only control the Touareg's behavior due to it's advanced brake system. Once again, these are add-on, piggy back systems that basically enhance\update the trailers simple brake system to a smarter, ABS like system.
Also notice how they had to add ballast to the trailer and do all sorts of maneuvers to induce the trailer sway. Once again, see my initial post about how you have another problem if you're experiencing sway.... improper loads, tongue weight, shifting loads, etc..... Most factory built trailers on this side of the pond will have 10-15% TW for stability\safety reasons. Overload the trailer or load everything in the rear of it, and you'll drastically change that balance.