smittybilt products ( their 3" tube bumpers mostly) are known to rust away. Looks like you have the smittybilt step bars too. I would suggest you ditch all of it.
As for vibrations, I would suggest you pull the hubs and take a peek. Probibly a good time to rebuild them.
heres a good writeup on how to rebuild them:
http://forum.ih8mud.com/79-95-toyota...b-rebuild.html
p.s where are your front turn signals?