Its a pretty in-depth procedure at least to do it properly.

I mean you can go and hook a few wires in here and there and get it to run but realistically it'll be a messy solution.

The main problem is that 20v looms are to suit a FWD where the engine bay layout is completely different. So to do a "proper" (and this is my own personal derivation) job of wiring a 20v you need to completely strip the loom apart and reorganise the loom to suit a RWD layout and of course connect up the relevant wires where they need to go.

You can also go one step further and add relays in factory positions which again takes more work.

So in short, yes there might be a rough hookup diagram somewhere but its not going to be a neat solution.