i have a pair of 15mm H&R spacers that i will be getting rid of as soon as i ship out my rims that were sold the other day.
you cannot use the studs on an S14 so you are going to have to buy new ones.
however… since you are going to buy new studs for the rear as well i can help you out if you are willing to change your thread pitch.
factory thread pitch is 12 x 1.25
i will also sell my front hubs that were taken from a 89 JDM silvia clip, i have ad ARP studs pressed into them with a 12 x 1.5 thread pitch (honda / domestic thread pitch) the studs are long enough for 25mm spacers without a problem.
then all you have to do is press the same studs in the rear and you are set. these studs are only $22 for a set of 4 as well, whereas nismo studs are $60 usd for the whole shoot and match.