Thanks for your tips guys, but after trying vigorously to take it off with vise-grips, liquid wrench and other various things I ended up taking it to my tech. At first he also tried the same methods I used but to no avail. He came up with something i've never seen before; he took a bigger nut and place it over the warped round nut, then welded them both together. He used a big wrench and presto it came off. Basically, all he did was make a new bolt over the warped one. I put in the new bolt, and I now have about 5 or 6 spare washers for the upcoming oil changes. Lesson learned--always change the copper washer when you do an oil change. Once again, thanks for everyones responses.
1989 300E ("E 300"-Badged)
Monotoned Astral Silver w/ rear lid deck panel
97 Style Replica E420 Rims 205/55/16
Black Grille Insert
Chrome Exhaust Tips
Pioneer Sound system w/ Sub-enclosure and CD-changer