My 2012 Prius has a pretty basic package. There is one unused button on the steering wheel above the Bluetooth phone pickup and hang up buttons. I'm thinking about a small mod but I am trying to decide how big of a hassle it would be to use that unused button. I'm guessing it would be a big hassle. There are also a number of other unused buttons (blank spaces actually) to the left of the steering wheel. They are likely much easier to access but much less convenient to use. Anyone have any experience with this that can give me some idea of the degree of difficulty?