Couple of things- I think I know of the dart you speak of, was it gold? If so, that was a nasty machine.

I knew someone who did a "swap" in a wrangler. The 2.4 bolted right up to the standard 6 speed the jeep came with. He had someone cobble together a better exhaust manifold and when it worked, said it was great, but could not get the tune to take advantage of the turbo and still be streetable.

Also keep in mind, if your just going to do a "simple" swap, the pt engine setup and out put are different form the neons.
Good luck, this sounds like a fun project