I just say 350z.
Most blokes know what you mean, in which case we have a chat about it and other cars.
If the person doesn't know what I mean, I just say "It's a Nissan".
I didn't buy this car to impress anyone, so don't care enough to try and explain the car to ppl and to justify driving a Nissan. If it needs justification, they aren't into cars and therefore, I'd rather talk about something other than cars!