Hey Jimbo,
There is the wet sump, which no longer is made, and the dry sump...The wet sump uses almost all of the same internals as the dry sump, minus
the oil pump and sprayers for the upper gears. The wet sump are like a bravo, which are full of oil (approx 4 Gal) and require a reservoir in the
engine bay (usually on the inner transome ring). The Merc dry sump holds approx 1 1/4 Gal of oil...
The plug in version has a tail stock that bolts directly to the trans and plugs into the gimble...The drive shaft version has the flanges to use a drive shaft. The NXT, 6, and 8 have the same bolt pattern for the gimbles...
We have the plug in version on the Cig and they are wet sumps....
Hope this helps....couple pics....