The Z is an amazing toy and while not
the best at any one thing, the total package is hard to beat for under $100K.
With one tiny exception (literally): The Fiat 500 Abarth.
The Abarth is half the cost, gets twice the gas mileage, weighs 1000 pounds less, and right out of the box is 80% of the 370Z's performance envelope.
And if you drop about $3k in bolt-ons, the Abarth will make north of 220hp, weigh about one ton with the driver in it, will corner with enough force to damage hot asphalt, and sound like it ate a Ferrari 458 for breakfast.... I say this as someone who owns and races a '13 Abarth with about $3K in bolt-ons.
There are some down-sides though: the Abarth is ugly as sin compared to the 370Z, has the typical Italian long arms - short legs seat position, you sit stupidly high in the car so it feels like you'll flip over all the time, and the car has a 90" wheelbase and is 55" across - so with any kind of sport suspension it's a bit like strapping yourself to a paint mixer.
Overall though, the Abarth is super cheap to feed and a hoot to drive. Taking one for a spin is highly recommended.