Yes that's the sway bar end link and it looks pretty shot. Cracks are no good. I've never had to replace one yet so I'm not sure on the procedure. Make sure you go with a good brand unless you really love doing the same work a few times over. Also check the bushings on your rear struts. I had a horrible clunk in my old bird due to that. And just a general rule I go by (and I'm sure many others too), If there is a part on both sides of the car, replace both of them.
I love my V8, but I'd love it more if all 8 cylinders worked. (they do now)
My T-bird is like George Jetson's wife, you try to give her a little money, she takes the whole wallet.
They are shot so they need to be replaced. Just remember you get what you pay for...... Buy cheap and get cheap. As for replacement....... remove the 2 bolts, remove the endlink, put new one in, tighten the 2 bolts. 15 minute job.
1996 TBird LX 4.6
2001 Sable Wagon 3.0 Duratec