Downgrade to CD player

I have the OEM MK3 navigation with 4:3 monitor and I was curious if anyone has had luck downgrading to the standard CD player? It appears the connectors are different the E46 looks to use the old giant style (sort of E36) and my nav system has very fine pins. There's two connectors on the back, I assume one is for steering wheel controls so that should be straight forward.



I know people upgrade to the OEM nav all the time, but would the process be exactly the opposite to downgrade as well?