"Where is your enthusiasm..."

Jeffblue

i think it is because 350's are at that perfect age and price which allow them to fall into the laps of your average joe shmoe who doesn't really care about cars. If you've got a z32 or prior, you have an old Z, and clearly, you like z's, because people don't drive 15+year old sports cars unless they are enthusiastic about them. if you've got a z34 you just bought a new car, and chances are if you're willing to drop more money for the newer version of the car, you're more enthusiastic about it than the person who says 'i'll just get a 350 because its cheaper (not that there is anything wrong with that).' 350Z could be anywhere from 3-7 years old, which puts them in an affordable price range for someone who is just looking for a fast, nice looking car, but not necessarily a Z enthusiast.

so more to the point, a Z enthusiast would be willing to either:
A: drive an 15+ year old car because they love it
B: Drop the extra cash to get the newest model Z around.

You don't need to do either of those things in order to own a 350Z, making it the most likely Z for a non Z enthusiast to own.