Utility
The Mazda MAZDASPEED3 will most definitely prove handier than the Nissan for those of you with frequent child-cargo.
Performance
In terms of horsepower, the Nissan 370Z packs quite a punch and will knock the Mazda MAZDASPEED3 down a few rungs. On the flip side, note that high horsepower engines often command higher insurance premiums.
Dimensions
Your wallet will hurt more every time you fill up the Nissan 370Z than the MAZDASPEED3 because of its bigger tank.
The Nissan 370Z and the MAZDASPEED3 compete for the same parking spaces.
Convenience
The Mazda MAZDASPEED3's fuel tank will need to be replenished more often than the unit in the Nissan.
Cost
The destination charge is a standard charge for transporting the vehicle from its point of origin to the dealer. It costs approximately the same to get the Nissan to the dealership as the Mazda MAZDASPEED3.
The Nissan 370Z won't save you much money at the pump compared to the MAZDASPEED3.
With respect to MSRP, the Nissan costs tremendously more than the Mazda MAZDASPEED3.
Handling
With its tighter turning radius, the Nissan is quite certainly more agile than the Mazda MAZDASPEED3, something to consider if you do a lot of city driving; however, keep in mind that a vehicle with a tight turning circle may feel a bit twitchy on the highway.
Drivetrain
The Nissan 370Z's engine is tremendously bigger than the Mazda MAZDASPEED3's. Remember that more sizeable engines may use more gas than smaller ones.
Torque is roughly equivalent to acceleration, and in this respect, the Mazda MAZDASPEED3 isn't much more powerful than the Nissan 370Z.
Comfort
While the front cabin in the Mazda MAZDASPEED3 offers a bit more head room than the Nissan 370Z, there frankly isn't much of a difference.
Overview
The Mazda MAZDASPEED3 and the Nissan have the same basic warranty.