Im with Ed. Don't so it. The money you save will be eaten up in hours of frustration. Not to mention now you have a used drivetrain of unknown origin.
at $9000 used you are saving at best $6000.00
you still need the following parts

Oil pan and pick up $600.00
Control pack at $1600.00
New mounts at $200.00
New gas pedal if not included $200.00
new shifter. one vendor was selling one for $800.00 I believe.

As you can see you eat up your savings really fast.
If you buy the drivetrain through FFR it all comes in one nice package assembled and ready to go.
Mike