i dont see how fabricating rx7 brakes to fit ek hub will even be adr approved vs the willwood upgrade lol.... but if it is, than it is...

If u only have a mild modded ek b18c, Ek9 brakes are more than enough... And they are 1 inch bigger than ek brakes, 282mm vs ek 262mm, as ive said above, u dont need to change stud pattern at all, just the rotors to fit the stud pattern

if ur still insistent on making the calipers fit, visit workshops as above, wont be cheap but.....

i believe rx7 use like 294mm or 314mm rotors, which is quite big for a small car like an ek, than tryna source rotors that size, and than fitting onto the hub, than also factoring the offset of rims and size of rims to fit over the larger calipers/rotor size