Utility
Neither the BMW 328 nor the RX-8 has a marked advantage as far as seating capacity.
Dimensions
The BMW 328's tank is roughly the same size as the Mazda RX-8's, though the RX-8's is a little bigger.
The Mazda and the BMW 328 compete for the same parking spaces.
Convenience
You will have to visit your friendly gas station more often with the Mazda RX-8 than with the BMW.
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 Mazda RX-8 to the dealership as the 328.
When it comes to gas mileage, the BMW 328 is somewhat better than the Mazda RX-8, but not by much.
The RX-8 is considerably less pricey than the BMW 328 in terms of MSRP.
Handling
With their comparable turning radii, the Mazda RX-8 and the BMW 328 definitely handle about the same into and out of tight spots.
Drivetrain
The Mazda RX-8's engine is tremendously smaller than the BMW's. Bear in mind that a smaller engine usually has to work a little harder; however, smaller engines are often cheaper to fix.
The Mazda RX-8 could learn a lesson or two from the BMW 328 as far as torque.
Comfort
While the front cabin in the BMW 328 offers a bit more head room than the Mazda RX-8, there honestly isn't much of a difference.
The BMW 328 is not particularly roomier for your passengers than the Mazda RX-8.
Warranty
The basic after-sale protection that comes with the Mazda RX-8 isn't quite as generous as the BMW 328's.