can anybody tell me if i can fit a au xr8 cluster straight into a standed au v8 and what mods to to do to make it work if needed

You can't just plug it unfortunately. Check out pages 22-24 in particular. usually the harness is missing the extra wiring in the low series even if the plugs are the same.
So it can be done...you just need to do some wiring mods/additions.