I have an S14 on which I have just installed the HAs and let me tell you that they are amazing. Easy install, great price for the quality, and great performance.
I'm not sure if they are being discontinued but they do have the new FLEX line out, which comes with a teflon coating on the coilover threads to protect from rust, have new valving and better design than the HA, come with upper pillow mounts for camber adjustment, and also give you the ability to install Tein's EDFC (electronic dampeing control unit), where you can adjust the 16 way stiffness from inside the car.
I'm not employed by Tein, even though it might seem so, but I've been so happy with their product and support that I'd recommend them to anybody.
here is the link with the specs/prices/part numershttp://
www.tein.com/nissan.html
good luck
hope this helps