I know the Mitsu engine and the Neon engines are not the same. The 420 exhaust empties to the front of the engine, the Neon's to the rear. That being said, they are very similar and I don't know if the manifolds bolt up or not.
96 Neon, 2.4, CAI, Hedman header, no keys!. Together, not running yet.
95 Jeep Grand Cherokee Limited(The Green Monkey)