2.0 DOHC top end on a 1.8 SOHC block!! Can it be done?

I have Gen 1 DSM with a 1.8L SOHC. Can I put a 2.0L DOHC Turbo top end on the block and make it work? Also, is it possible to install a transfer case on the stock FWD 5spd manual trans-axle or do I have to replace the whole trans-axle to make it AWD?