The guides are out of date Using privoxy isn't as bad as using polipo. But right now the official suggestion of the Tor project is to use nothing and just point firefox at Tor. Actually the official suggest of the Tor project is to *only* use the tor browser bundle, and failing that you should be using firefox with the TBB patches (not going to bother digging them up right now sorry), and failing that using a live CD distro that applies the TBB firefox patches (tails does, not sure about liberte).