I beleave the OE,s have Arneson/ Second Effort 16 inch drop boxes.
They are a very dependable drive. Some things to look for.
Check the gear oil for water. The screw is right behind
the skeg. The drop boxes have transmision fluid in them.
It has internal chains.
They do not offer counter rotation so this is usualy done in the motors.
Parts can be a little tricky. But outside of hitting something
you wont need any.
They use a 19 spline long hub prop.
There fast and efficient.
Reverse can be a little tricky but being on cat they will be better.
I wouldnt hesitate to own another boat with them.