I feel you there dude. Before I bought my car, the guy had just taken it in to get the oil changed so I didn't bother with it right away. A few weekends ago I go to change the oil. Drain all the oil out. Put the plug back in. Go to change the filter. Can't get it loosened up. None of my tools fit to crack it loose. The thing was like stripped and scraped up the way you said yours was too. I laid under that thing and got so pissed I grabbed it with both hands, squeezed it until it started bending inward and then turned it a couple millimeters. After about 20 minutes of using all my strength to get the thing turned 10 millimeters or so, I said fuck it and stabbed a screwdriver through it and twisted it off that way. Still took a shit ton of work because it was on so tight that the screw driver was just shearing through the metal. Took me over an hour in all to get the damn thing off and pretty much ruined my entire day. Put the new one on by hand so the next time I'll be back to my normal 30 minutes or so.