Probably no one's ever put together a kit because everything needed is available over the counter except the engine harness and manifold components. It uses all stock V6 Fiero parts. You'd need the engine harness up to and including the ECM and you will need to get the starter relocation jig from Rodney. If you could grab a blown engine from a Fiero, strip all the parts and transfer you'd save a lot of money as opposed to buying stuff by the piece, and you'd be sure you have everything you need.
Which Winchester are you near? If it's Virginia, check out VAFA at http://www.vafieros.com/
They may know of something close to you.