I don't have Vario cases. I have BMW Pannier and top case. I ride with them all almost all the time, I am in California and find that it does not really interfere with splitting lanes, as long as you know that you cannot zip in and out of traffic. You have to remember that the rear is as wide as the front when you are coming back into a lane.
Sport Riding in the twisties, I have the pannier /top case loaded with gear/tool, supplies . I have not encountered wobbles or instability. That's averaging 80-90 on freeway. I have gone over 110mph with no issues at all. Concerning at times since the pannier/top case says do not max 88mph I think.
I keep them on in case I go somewhere I can bring regular shoes, store my helmet and jacket instead of dragging in with me.
I received a free BMW duffel bag , when I purchased bike when they had reflector issue and couldn't purchase panniers. So Dealership gave me bag for the trouble. I'm looking forward for opportunity to use them attached to passenger seat with fully loaded pannier on an adventure.