well, what do u plan on doing to the rx7, if you want performance the best would be an s4 turbo2(87-8
because it has lsd and all the little goodys pluse you can run more boost with the s4 motor, if you want comfort and all the interior goodys go with a 91, just remeber the turbo has almost every option, and the gtu also has almost every option without the turbo motor.