I like it.. and will consider using the badge on my car as well.
You can't compare it to someone who had a base model Mustang and converted it to a Cobra then slapped the badge on because you can actually buy the Cobra.
To me, our 370z are the same thing as the FairladyZ.. there's no even more top end model that you can buy, I think by using the badge, you're just paying omage to it's Japanese name. It will also give your vehicle a small sleeper look leaving people wondering what you're driving
Edit: My girlfriend laughs at the fact i'd consider putting "Fairlady" on the back of my car.. she thinks of it in the girly-man sense lol.