GKTech has a nice write up of S13 vs. S14 subframe differences:
https://blog.gktech.com/blog/s-chass...me-comparison/
They also now sell a "anti-squat reduction weld in kit" for the S13/R32 subframe (maybe that's why people are going back to S13 subframes?):
https://us.gktech.com/s13-240sx-r32-...on-weld-in-kit