First off when you do place both drives into RAID 0, you will need to reformat the computer with the third-party raid installation. Meaning you will still need to backup all of your data before hand to enable the RAID. (There may be another way around it. Every time I have set up RAID, I have always done it through the reformat system).
Second, yes you can make an exact copy of your computer (OS/Files/etc). I prefer using Norton's Ghost (http://www.symantec.com/norton/ghost
). I have used this on multiple instances. This is also great for backup purposes when you want to just store a DVD-RW of your files in case your hard drives do take a dive.