[The Rooster]

I think the lack of transmission is your biggest obstacle here. The easiest thing to do would be to source the right Porche tranny and build an adapter plate from whatever engine you want to use to your Porche tranny. If you decide to use a different transmission, you are going to have all kinds of problems trying to make CV's work. Very few companies, that I'm aware of, do custom CV shaft builds, and they are very expensive.

I think this is a bigger issue than the engine size, transverse or inline, upside down or purple, before you do anything, address how you will handle the CV shafts.