"CADWorx Plant 2006" is an AutoCAD add-on, it's sort of popular from where I am (Calgary, Canada). It's 3D, and sort of parametric in the way it's used, and has the ability to import 3D objects from other CAD systems as well as probably export (since it's standard AutoCAD 3D stuff). I think a seat of Cadworx costs about $1500 or so.
There's also the even more 3D packages, like a piping module made by Pro/Engineer. It will tend to cost more, and possibly be more complicated and way more expensive to use though. Expect this combo to be $10,000.