I had a go at changing my front O2 sensor tonight and got screwed. I didnt have the tool and could not get to sensor anyway I tried. What pain in the axs. I dont know why subaru doesnt put a notch in the heat shield so you can actually pull it off and get it out of the way. Anyway, long story short I clipped the wires on the sensor thinking I could get a deep socket over it...not go. So, now Im driving without an O2 sensor at all. Im in Juneau Alaska at the moment and I dont think I can get a shop to rent me a tool...but out of curiousity was it just a socket with the side cut out? Any other pointers to get this job done with less blood and tears?