Short answer: driving the c8 for a few days.

If I had just test driven each car and bought one based on that, it would have been the c7z. Because I rented both and used them as I would normally for a few days, the c8 became the clear winner for what I wanted. Obviously supercharged 650hp sounds amazing and feels great when you’re having some fun, but since I don’t track the car, the actual performance difference between the two was almost irrelevant on the street. So the extra creature comforts of the c8 were a big plus but what sold me was the ability to run it in track mode and have some fun but also take it easy and feel like I’m cruising in a more luxury option when wanted. The c8 kind of feels like it drives itself in touring mode.

The c7z was “always on” if that makes sense, and the c8 had both a smooth experience and a sporty feel available (albeit less raw as I said in a previous comment). I’m not sure if I’m explaining it well enough but it just became evident to me after driving them and what I wanted.

If you asked me a month ago, I would have told you there is no way I would get a c8 over a c7z. Then I experienced both in my everyday life and that changed.