Thanks so much for the feedback.
I've never had a problem on clear asphalt with the abs (dry or wet). I should say that the abs modulator in the car is actually not the original one. It was replaced about a year and a half ago with one pulled from another subaru (my original unit was leaking brake fluid). But over the summers it seems to behave fine, and it takes some serious braking to trigger it.
I guess the deal on the slush is just that these couple of incidents have made me a bit nervous about the whole stopping ability of the car in these conditions - in both cases I was really going pretty slowly down the street, and the road was more messy than covered, but the car seemed to just sail through the stop sign (but was accompanied by the shuddering, so I guess it must have been braking some). Now of course I don't know what would have happened had the abs not engaged, and I realize that the abs might have been doing exactly what it was supposed to, but it was just my gut reaction that it took too long and that I would have been able to come to a stop sooner had the abs not kicked in.
The default I guess is that I leave things as they are, as at the moment I don't actually know how to disable or adjust the abs (I'm not really much of a mechanic.. so tinkering will require the help of a pro unless its super easy). I was just curious if there was an easy way of disabling it in case I am out on some ski trip and really start having problems, or if I should take it in to see if it needs adjusting. I certainly don't want to start voiding insurances or doing anything illegal anyway...
The strut issue is interesting (hankosolder2), also the single wheel sensor issue (skid542). Which wheel is the sensor on? Might tell you which wheel to take a closer look at. I also need to get a slow leak fixed on the front left tire, although the abs issue preceeds this.
Thanks!