This has been answered a million times
The driveshaft will work fine. I used my KA driveshaft
The tach from the sohc will not work correctly, so most people swap out the cluster with one from a dohc or the cluster from their front clip.
The power steering lines do need to be changed if you want p/s. Many people run w/o it, including me.
I think the a/c compressor from the sohc doesn't bolt up at all to the SR, so if you want a/c you will have to get custom lines made or get a S13 DOHC compressor. Or just run w/o a/c. I ran my stock compressor.
Most anything you would ever want to know has been covered if you search a little or check the faq.
http://www.srswap.com is a great site.