i have done a coilover conversion on my s12, bought a full set of TEIN coilovers for a s14, (cheaps!!) and the pillow ball top mount was a straight fit on my mk1, i used the lower arms, hubs and tension rods of the s13, mainly as i wanted bigger brakes and calipers and the s14a 4 pots bolt straight to the s13 hubs,
My plan too. Mainly for the adjustment introduced and brake options.