1. The firmware you can instal later, will not erase your data.
2. Is no need to keep your files and apps separately. Only movies or iso images etc.
3. The Trim function is only in windows 7 and will work in AHCI mode (bios) with msahci driver only. NTFS or FAT32 doesn't matter. I don't now what about Mac OS.
4. Always use quick format.
1. If the OS hasn't been installed, update any firmware first. It should also work after installing the OS.
2. Many users seem to be concerned about the writing to their drives. Don't be. The minimum useful life is considered to be 20 GB per day for 5 years. No counting the initial image copy, I've written less than 200 GB to my SSD in one month. So, at that rate, I'll reach the minimum data written in about 15 years, or long after the useful life of the drive in time. I have the pagefile on the SSD, indexing is turned on. I keep large data off the drive, but that's as much because I want a smaller amount of data when I back the OS partition to an image.
3. No it will not mess up anything. Trim simply tells the SSD that blocks previously used by the file system of the OS that is running are no longer used. This allows the SSD to organize the space during idle time so that future writes may take place at maximum speed. Manually running a tool in Windows 7 is not required because NTFS and the MS AHCI driver both support trim - ie both the file system driver and SATA controller (AHCI) driver must support trim for it happen automatically. The Intel AHCI driver is expected to support trim in the future.