sorry just saw this - but I just BARELY did an o2 sensor change on my 92'.
The connectors are the biggest pain for the job.. they're the same type clip for the ignition coils and they're a bit of a pain to get to..I would slide them off the bracket off the car so you can twist the connector around and at least see what you're looking at. The o2 wire has some slack so you can pull up on them a bit because you don't want to stress the wiring harness. A small screwdriver in the right place and the plug will let go.. Subaru designed those clips to never come off on their own and they do a good job of that...
The car will run semi ok but probably like crap and will run rich..without them plugged in and I'm pretty sure you'll get a check engine light. Mine were bad with no check engine light and when I pulled the plugs the spark plugs were fouled and wet with fuel..
Also this might save you but.. my car had a major hesitation issue and no check engine light. I threw parts at the car and was about to spend hundreds of dollars on a mass air flow sensor/TPS... someone mentioned that you have to reset the ECU to recognize the new o2 sensors I installed. After I did that the hesitation issue is gone...car runs WAAAY better.. little vibration and I'm thinking the injectors need a cleaning but those o2 sensors can really make your car run like total garbage when they're not working right.
If you do unplug them for a good amount of time and replug them in.. I'd make sure you disconnect the battery for a good 10+ minutes (I let it sit overnight) so the ECU will reset and relearn the mixture or else it'll still run like garbage after you plug them in.
Hope that helps :/ good luck on those connectors..