Rear engine hydraulic pump system option

[Lflonghi]

I have thought about the possibility of adding a second hydraulic pump that goes to rear engine. I hear that it's a back up in case you lose the front engine and also when all is operating runs the whole system faster.
I hear this was an option from Cessna long ago. Does anyone have any info if this is 1) works as advertised? 2) has any down sides? 3) know where any documentation exists on how to install and parts needed? 4) knows where to get the parts? Thanks Lou