the 13b REW is an engine which was first seen in the second generation RX-7 also known as savana code name (FC3S)
the same engine was also used in the third generation also known efini or (FD3S) with minor tweaks
the reason to tell you all this is to let know that the 13B rew grew in terms of performance as the years passed and mazda engineers got more familiar with the motor
the 280hp mark that you mentioned was brought out in the series 8 rx7 which were only sold in japan , the series 8 rx7 were the last of the series for rx7
the models that were introduced in series 8 rx7 are
RX7 TYPE RS (1999) (280HP)
RX7 TYPE R (1999-2000) (280HP)
RX7 TYPE RZ (2000) (280HP)
RX7 TYPE R BATHRUST R (2001-2002) (280HP)
RX7 TYPE A SPRIT R (2002) (280HP)
EXAMPLE OF SERIES 8 2002 rx7 type R bathrust R
RX7file:///C:/Docufile:///C:/Documents%20and%20Settings/Nahid/Desktop/mRide_34336.jpgments%20and%20Settings/Nahid/Desktop/mRide_34335.jpgfile:///C:/Documents%20and%20Settings/Nahid/Desktop/mRide_34339.jpg
file:///C:/Documents%20and%20Settings/Nahid/Desktop/mRide_34340.jpg