Me too
I am also wanting to replace the Getrag in the W-350 with a NV4500 or NV5600. I know from drivetrain.com it costs about $2200 for a transmission, bellhousing, etc. to get a kit. This price doesn't include a clutch. Not 100% sure about the cost of the NV5600 job, but I am sure it will be more expensive. I am going to wait until the ol' Getrag goes BOOM before I worry about it too much.
Jeremy