That's very unfortunate. Me and my wife each own Jetta's. I had an '07 I just traded in for a TDI and her's is an '08 both with the 2.5L. We both put over 80K mi on our cars in less than two years, and I haven't noticed any sign of timing chain issues. I'd like to think the 2.5L is a solid engine, but it does sound like you may have ended up with a lemon for an engine. There is no reason why the timing chain should have catastrophically failed like that, short of bad maintenance. I certainly hope your rebuild lasts you much longer. Good Luck!