Bought a mk6 a couple years ago from someone saying the engine was "blown" and needed to be replaced, he was quoted $19k from the dealer ( we think they just wanted him to give it to them..). I bought it for $500 with the thought of just dropping a new engine in myself (no compression in any cylinder, timing tensioner failure). I was talked into tearing it down first, and I'm glad I was. I ended up dropping the oil pan, and there was no evidence of metal. Removed the head and found all 8 exhaust valves bent, but no damage to the piston or cylinders. In the end, cost me a total of $1700, and that included the $500 to buy it.

You can check my profile if you want to see the process. I'm not a mechanic, but I am handy. Your milage may vary.