Concern is that the ECM may not like the different voltages that a smart regulator will use in normal functioning. The OEM reg function appears to seek to always make the system voltage the same regardless of battery need. No idea how much flexibility the ECM has to compensate. In our case all the ECM does is control the trans, has no engine control functions but does have engine sensors.
I would opt for an OEM dual alt system if one exists. Not a lot of faith in the aftermarket. They usually don't understand or bother with stuff like MTBF evaluations.
The one thing that can really mess with you when doing something like this on a 6BT is that there are apparently many, many different fan idler brackets that place the fan in different locations. So need to find a dual alt. application that is similar to the existing install so that it places the fan in the right spot.
