How should I respond to the Nissan 370Z?

[boxster1]

I love my Boxster S and I'm probably going to buy a newer one, or a Cayman S, next spring. However, the performance of the Nissan 370Z has made me ask the question, "why am I paying so much money for a car?" In the end, all I can come up with are personal reasons why I prefer the Porsche, and almost nothing quantifiable.

How can I argue with my relatives when they ask me, "why did you buy a Porsche when a 370Z is just as fast at half the price, is probably more reliable and cheaper to maintain?"

Is the 370Z a "game changer"? Is it the meteor that has hit the dinosaurs?