None of your points are really correct. Warranty is only void for specific repairs determined to be directly caused by the modification. You are never liable for anything that you didn't cause. It's not as if warranty and liability are a binary value that changes if any part of the car becomes tainted.
We've been modifying cars long before computer games, and in far more intrusive ways.
We've been modifying cars long before computer games, and in far more intrusive ways.