Where can I get these parts and fix this?

My drivers side seat is loose and the nylon/teflon strips on the slides that the seat slides on is worn out so I need to replace it, does anyone know where I can get just this nylon strip? I also need to tighten up my steering column because it is loose, I tightened up my rack so my steering is tight but my steering column is loose. Lastly my door is sagging and I want to adjust it or shim it so its perfect, can I just adjust it with the bolts or should I get new pin and bushings for the door hinge? Where is the best place to get these parts?
Thanks for any help.