Will this TDI work in my Jetta?

[57ringo]

My M3 99 Jetta TDI burned up a piston. I found a TDI that's supposed to be out of a 99 or 2000 Beatle that someone changed the timing belt wrong and belt some valves. I was going to look inside the cylinders with a bore scope to see if it looks ok. Will it fit in mine? How do I tell exactly what year it is and if it's what I need? It had a cast valve cover and pan and a few other things different. They said it only had about 40,000 miles on it.