An Eclipse motor (4g63t) will not work unless you have the money for custom work.

Evo IV and up motor will work... Evo I, II, III will not work. You can find out more information at Mirage Performance Forums :: Index like qbanjr posted. There's a few on there who have done the swap and some locals in Florida who have done it to their Mirage. A few in Orlando. Evo IV seems to be the popular swap on 97-00 Mirages.

Good luck!