It's my understanding that the reason the S13 SR FMIC kits dont work is because their throttle bodies are lower and the cold pipe angles down where it connects.
The S14 SR has the throttle body in a similar position as the CA so the cold pipes are interchangible.
I'm not sure if the S14 IC core has different mounting tabs or not tho, therefore ideally you'd want an S13 SR kit with S14 SR cold piping after the IC.....but since the piping is the harder part to get ahold of, people just get the S14 kit and change the hot piping.
You could always just buy the S14 piping and peice something together if you wanted to save money or already had a core. I believe this here:
http://cgi.ebay.com/ebaymotors...%3AITis the same as the Hybrid piping (which I hear originates in Hong Kong as well).
-m