94-97 will interchange. The most important difference is the thermostat. A 96-97 thermostat will not fit in a 94-95, as it is about 3/4" longer. If you put a 94-95 thermostat in a 96-97 pump, it will fit, but will not block the bypass port.
This can lead to overheating in parts of the engine even while the gauge reads normal!
If in doubt which pump you have, measure from where the thermostat seats to down inside where the bypass port is
(Webshots PIC) . Approx 1.5" on 94-95, 2.3 inch on 96-97.
While expensive, you can also upgrade to the International Pump with an integral coolant filter. There are some threads with good descriptions of this, but until I can search the archives I can't get them for you. Maybe someone has a write-up [img]/ubbthreads/images/graemlins/shrug.gif[/img]
