It may have a Detroit Diesel engine or a Duramax.
I don't have any personal experience with the Detroit Diesel or Duramax engines but they seem to be well regarded. 2001 was the first year of Duramax production and the common problems were injector failure, overheating and blown head gaskets. It was a pre-emmissions engine. Here's a link to the Wikipedia articles.
The body is a Bluebird which is considered a well built body. It's from Ontario so there may be rust issues but the mileage is pretty low so maybe the rust is minimal.
Price is about par for 15 year old shorties.
It would be nice to have more condition history and service history but they probably won't give it to you. The lawyers have put the kibosh on that.
Is it driveable? They aren't saying. I'd want way more info before breaking out my checkbook.