your best bet? strip your s12's engine bay of pretty much everything and start with a clean slate.
drop the vg30dett in there, see what kinda clearance you get, and go from there with your extras.
you'll need to fab, relocate, and fab smore...but if you're adamant, it can be done, obviously.
I had no info on my swap going into it and I got it done anyway, through trial and error.
just dive in feet first.