Actually, if you Google "nissan S13 S14 rear caliper comparison" you will see other websites that explore this exact issue.
Because HybridZ doesn't always have the answer I want I have joined other car websites such as for Toyota, 240SX, Nissan as well as other Z sites.
When all else fails, I go to pick and pull and buy the part in question to use in mocking up and test fitting.
Perhaps if you work up a solution to your S14/S13 issue you would post a tutorial on how you solved the problem.