My new to me 03 EB has what I describe as a slight click / clunk and it appears to be under the driver's seat. I can only hear it with the radio off. I took a look under the truck and looks like the sway bar is in the area I hear it. I am going to guess end link clunking? Should it be replaced?

 

You're probably right with your guess,check with a pray bar, all your sway bar and links bushings, for any play.