For one, he's day dreaming. When he has the car & makes a thread asking for advice, you can be sure most of us will be there.
Secondly, you're right, it isn't wise to track a daily driver. However, we have to be realistic. In the case of which car is better suited for daily driving & track abuse, a R34 GT-R is a much better contender because Nissan built it that way in the same way Ferrari builds Scuderias or Porsche builds GT3/2/RS models. Your Impreza Wagon wasn't. It doesn't have parts on it designed to cope with the harsh effects of a track day.
Again, it doesn't change the fact that yes, it isn't wise to track your daily driver in the event of something breaking, but a R34 GT-R will take the punishment much better. The likeliness of a problem occurring from a track day is you warping the brakes on your car whilst the 4-pot Brembos on the GT-R will most likely just lose a small chunk of their life & speed up the maintenance interval on them.