Well, to begin with my dad's Boxster is just a Boxster, not a Boxster S. So the Z has 80 more horsepower than the Boxster, while the Boxster is only like 200 pounds lighter. The Z mops the floor with the Boxster in a drag race. But the reason I really went with the Z over the Boxster is because I've always loved Z-cars. As a little kid, my dream car was the 350z and when the 370z launched it was everything I wanted and more.
I also looked at a used Ferrari Testarossa when I was looking for a car. The car was a bit out of our price range though, we were looking from 20-30k and the Testarossa was high 30s. I feel like if I'd really pushed for it I could have gotten it, but I was too excited about getting a car so I was willing to settle for something like a used M3. My mom didn't really like the M3 though because even though it was priced really well, she felt like the interior quality wasn't up to her standards which is what pushed us up into the next price bracket that allowed me to get my Z.