i have done a full s13 coilover conversion so it is slightly different, but on the s13 hubs, a bolt on four pot conversion is the s14a, and they will go over the larger s13 facelift discs, i believe 289mm (but dont quote me on that!) thats the brakes i am running and the seem more then adequate and still run under 15 inch wheels.
I looked at putting the s13 hubs on the s12 struts but came to the conclusion very quickly that in might be less work to modify the cross member and tension rod mounting points to suit the s13 lower arms coilovers, and braking options.
just my 2p
good luck with the mods
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S13 running gear, independent rear suspension, coilovers all round, il post a thread sometime...when i get a chance!!