anythings possible with money, engineering and fabrication, but most tend to go down the ek9 route as its more than enough for the car, anything bigger than they usually opt for willwood or spoon 4 pot calipers.

imo, i dont think the ek Brake booster will handle the Rx7 brakes, as they are much bigger, which is why they prbz wont work effectively...

and....You dont need to change ur stud pattern at all, just swap out the calipers and rotors with a 3 mm spacer, add the ek9 Brake booster and MC and ur done....