Is it possible to switch from default RAID0 stripe to AHCI?

In the past weeks, I spent 50+ hours trying to migrate to a clean Windows 8 on my VPCZ1390X. It took a catastrophic crash that buried nearly all my data. In the end, I succeeded (Word to the wise: Do not assume that when you reinstall, Windows will create another windows.old.old directory. It will just delete the previous windows.old. After all, some MS techie though "What might possibly go wrong with deleting old user files instead of letting them delete a .old directory themselves?").

Today, I realized that I was going to try out the AHCI mode on my next OS reinstall, since it might support TRIM, and is rumored to give a performance boost. I actually dislike the RAID configuration which shows 4 SSDs as one. I never worried about having multiple disks in the past. It is, in fact, the way I'm used to organizing my data, and makes me feel safer in case of a hardware error. Though any of these assumptions might be wrong, as despite my best efforts, I cannot get reliable information on RAID and SSDs. The amount of conflicting information just made me throw up my hands in the air, and consult here.

Now, I dread reinstalling Windows 8 again. I don't remember the exact steps I followed to make the VAIO components work so seamlessly. I do remember how much time and effort it took me, and I don't want to go through it again just for a minor performance gain.

So, my questions:
1- Is there a noticeable performance gain in switching from RAID0 to AHCI, or vice versa?
2- Does Sony VPCZ1390X really support TRIM on AHCI?
3- Are there any benefits to RAID over AHCI on matters of usability, security, and performance (I only perceive having a single-volume instead of four)?
4- Is it possible to go from a RAID volume to AHCI without reinstalling the OS? If yes, how?