I downloaded this japanese video from BT where they had a comparison between a few roadsters. Let me see if I can remember them. There was a porche 911 carrera, c6 vette, bmw z4, Lotus Elise, Mazda RX-7, and Mazda Miata. I don't understand japanese so I dont know what they were saying but from the videos of the run, the vette was just sliding and swerving all over the road. It received the lowest ranking according to the driver. The porche was on top followed closely by the z4 and rx7. I'm assuming they are only stressing handling and not raw power as you probably can tell the miata isn't even in the same league.