If you want to do a clean installation, spend the money on the OE mounting plate which bolts onto pre-drilled holes on rear right steel member. This saves you from having to drill holes on the inside bottom to mount the CD changer.
The CD player may or may not fit on this MB tmount. Ask the car audio shop to drill/rivet the 2 metal brackets for holding the changer onto the mounting plate.
At least that's how I installed mine.