I did not explicitly test what happens but you will end up with two rSAP servers on your phone. I don't know which one will be used by the car. Perhaps this even changes every time? But you cannot break anything. If it does not work simply uninstall the system files and the app and everything is like before.
You will at least have to root your phone to try.
I would recommend to try CyanogenMod, but it is a bit complicated to return back to the original Samsung ROM in case you don't like it.
It fails on my i9100G . it does not recognize the phone. I got a red message saying "are you on htc or samsung phone ?" or something close.
I aslo tried to test Bluetooth.apk you did with no sucess.in system/app I only copy the file. I did not find Bluetooth.odex, so nothing to delete. after reboot error message. I wonder if bluetoothPbab.apk would be better candidates to be replaced ? what do you think ?