So, will 3 Vertexes go over 650MB/s? I've read so many reviews/experiences, I can't remember if 3 of those drives will.
For best performance, the caching on the PERC might help a little, although for Vertex drives it probably won't do much. For slightly fewer headaches it might be better to use the onboard RAID for booting from a 3-Vertex RAID0 (as booting from RAID cards can be troublesome, especially on desktop boards, and even more so if you also use the onboard RAID functions or have NICs with a BIOS).
To update the SSD firmware I would advise you to use the onboard ports, without any RAID set up at all. For more info you would be best off checking out the OCZ forums.