the r32 coilovers will fit up fine just make sure you dont get the gtr ones. there is no problem with 4 stud however if you want to change to five stud all you have to do is buy the 5 stud skyline hubs.
i would spend the money on a good lsd makes a big difference, i would also get solid cradle bushes, with the de engine you will need all the suspension help you can get, i would also get some urathane caster bushes.