Lucast,My O2 sensor fought me the whole way.I thought I stripped the manifold out when it came out.Heat is one answer,and in the past I have broken the end off the sensor and used a shallow socket to get it out.My worst case was Having to pull the manifold off and clamp it in a vise then heat it up to get it out.AUNS-always use never sieze on this when replacing.
With fuel filters I hold the filter with a vise grip or crescent wrench and use an impact wrench on its low setting to get the darn banjo bolt out.I Neversieze the bolts with a small amount so maybe it will come out more easily the next time.I have always had trouble with getting the banjo bolts out on the Fuel filter.I have used a long handled rachet but I had to jack the car up so I could pull on it.It took 2 people-I had a friend keep the fuel filter from twisting with the vise grip pilers.It was a mess,fuel leaking out everywhere,undercoat dissolving in the process and getting on everything.Good luck!