+ ECU/TCM, harnesses etc etc etc.
IF you have access to cheap parts AND you're mechanically inclined and have access to a lift etc etc etc, it will be DEFINITELY and INFINITELY easier and cheaper just to trade in the auto for a manual.

People ask that all the time on the elantra boards I'm on. Only one guy has successfully pulled it off, and it was a PITA- I think it was down for several weeks. He bought a rear-ender write-off for dirt cheap to get the front-end parts, was a tech with tools/lift/time but still had a hell out of it.

I'm not saying you can't do it...