when I took off my midpipe, I had to remove the passenger side o2 sensor when it entered the pipe (not just disconnect it), so I cut off a small peice of the clip to get a 22mm star sided wrench over it, broke it loose.. then unscrewed it by twisting the wire over and over... then I used a 18mm socket, swivel, 16" of extension and a breaker bar (for ease, I did it with a regular socket wrench later for the other side).
the 4 on the midpipes are easy (mine was rusted tho, so that was a pita)
once all the bolts are off, you push the catback back a bit, and pull the exhaust down.. give it a little shake. the gasket on the passenger side fell off for me - so make sure you put it back on right if it does.
thats what i did :x
the first time I did it, I had it jacked up a few feet (the entire car) I took it off again alittle later, and did it on regular car ramps