Its in the front driver side of the car. it attaches using clamps to the airbox. The big black plastic cylinder shape. like a drum. un-clamp the 2 clamps holding it to the top of the air box, and then unscrew the hose clamp on the other side. it should take no longer than 30sec to do.
I second Tom's. I bought the engine that currently sits in my Volvo and it has been working happily for more than an year now. I may yank the head out sometime soon but that is because I want to cut some grooves on it. Otherwise, I am quite happy.
On the other hand, I did see a 95 ng900S in the local yard. But, it has a 2.3 engine.