Originally Posted by KA24Tech

The original CA20E is a good engine but if you want the most compatible engine with more pep it would be the FWD CA18DET. You can do a full SR20 conversion but that means you have to do several mods to the mounts, crossmember and of course all of the engine electrics. You can swap in a KA24 but I would use a DE from an Altima and use a Stanza trans and crossmember.
The thing I would do is get the CA20E running right by going out and getting a Haynes manual for it, looking at all the major tune up components and then considering an engine swap.

Troy