TRIM doesn't make a drive faster out of the box - it prevents the drive from getting slower over time as more and more of the flash cells in the drive become "used".
RAID can improve transfer rates but not access times. If you copy a lot of large files then RAID could help, but if you're looking to speed up tasks like booting and starting applications then you're not going to see them going very much faster.
Neither, I think. I would get a single larger SSD with trim. The reason is that a larger SSD will have more nand chips inside. That lets the unit access more of those chips in parallel. Sort of an internal raid-0 if you will.
The value of a SSD is the miniscule access time. Most of what we do is small reads and writes so the maximum transfer rate is only if interest to synthetic benchmarks, not actual usage. As siminlal said, the value of trim is in keeping the write performance up.