I haven't tried this on a 5g, so don't bother asking me if it works. What I can tell you, though, is that it works on the S2k which has much pickier electronics when it comes to secondary O2 (cat) performance.
This comes from this thread at S2ki.com:
http://www.s2ki.com/forums/index.php?showtopic=229959
This modification effectively reduces the amount of exposure the secondary O2 has to the exhaust stream. This mod will allow the 5g and '96 4g guys to avoid the CEL for poor cat performance without having to do the dubious OBD2 "workaround" and pass OBD2-based emissions testing.
