I have driven the 2004 Mazda RX-8, but it was a 6 speed manual, which is more fuel efficient and much faster than the automatic.
You will get an average of 20mpg.
This car can go on long trips.
This car has a rotary engine, which is different to maintain than piston engines found in all other cars.
Only use 5w-20 regular oil. Do not use synthetic, or high mileage oil on this car.
MAke sure it is driven every day. If you do not drive it for 2 days, it will not start and the engine will need to be decompressed. With Rotary engines, you need to keep the oil in the engine pumping and keep it from getting hardened.
If you go on vacation and leave your car, it will not start when you get back and it will need to be towed to the Mazda Dealer.
If you know how Rotary engines work, they can easily last 150,000 miles. These engines also burn oil faster, so oil changes are different than other cars.
Check the compartments for a book that came with the car. It is the owners manual. It will tell you how to take care of the car and teh maintenance schedules.