Car owners who have not suffered a loss should indeed be allowed to sue the automakers. The car owners could have potentially had a loss if the info was hidden from the public for such a long time, and without warning. It is only right that everyone profits off of the lawsuit, then the car makers will think twice before sending a car on the road that is flawed.
GM knowingly lied about the safety of their vehicles. This caused several people to die or be injured in otherwise preventable accidents. General Motors did this to save a small amount of money. Though, obviously, the company should pay big money to the victims' families, those who bought the cars should also get money because they were lied to and endagered.
I don't feel car owners should be able to sue automakers for loss of brand reputation, as if this was the case, where do you draw the line? It would be the same as suing Coke because some piece of bad news got out about them. The people who bought cars from General Motors have a working car, which at the end of the day, is what they paid for.
No, car owners who suffered no direct damages should not be able to sue auto manufacturers for loss of brand reputation. If you were not affected directly, you should not have any right to any sort of retribution. Your car loses value immediately after it leaves the lot, and regardless of the brand will still be worth a certain amount over time.