Import, I hear what you're saying and 'get it'. However, Nissan specifically targeted the 370Z at the BASE Cayman, BMW Z4, and the Audi TTS. Not the Cayman S, Z06, GT500 or even the Mustang GT or Camaro SS. They didn't care about price points except that Nissan's beat all three of those competitors. Nissan wanted base Cayman, Z4, and TTS blood and essentially got it at the time the 370Z debuted.
Remember this?:
http://www.bmwblog.com/2010/08/14/ne...n-competitors/
We the consumer, given our budgets and general interest in performance then make all the analogies you provided.
Suffice to say that the Z performs well, beats out the three main competitors that Nissan initially targeted, and makes the majority of its owners very very happy.
...and to the last posted question: the oil is cooled by air, with or without a cooler.