I would be real careful about that craigslist item. Can't really tell for sure, but that engine looks a bit cheesy to me. Whenever I see a 3-hole head gasket, I think it's someone who doesn't know how to check piston deck height. And that head looks like it could be Chinesium to me. I always think if they can't take a clear picture, they are trying to hide something. An old OEM TDI head is 100x better than a 'beer can' CRAP head.
We have plain blocks that are bored and honed with torque plate to fit pistons we have in stock. Nural pistons. The block would need to be decked for piston height.
You haven't given a single bit of detail. What happened and how much damage? You'd be surprised what we are capable of accomplishing.
Of course, the TDI and IDI are not interchangeable.