There is one guy that has managed to do anything near what the mags can and he had years of drag racing experience, powershifted, and also went through two tranny's and blew an engine. He also claimed to have slips and video but failed to produce them and disappeared from the forum when people kept asking for them. Other than that the fastest time that anyone has achieved is a 14.8 and there have also been more 15+ second passes than there have been 14 second passes. In person I've seen anywhere from 15.1-15.8 with traps around 90mph at The Grove and those were all the MT version. The AT is a 16 second car and is dog slow.
The early magazine reviews where the car ran 14.5 were all done with preproduction cars before Mazda had to change the ECU settings to make the car run rich in order to preserve the life of the first cat. In addition in order to get the car to do a 14.5 an 8k clutch drop was needed, and that clutch drop often brings bad wheelhop which seems to be fairly common on the RX-8.
In the twisties they are great cars and handle very well, but they are not all that impressive in the acceleration department. From a roll up to high speeds the RX-8 would probably take out a WRX, other than that the RX-8 should lose in a straightline.