Not to worry.
AHCI is a subset of raid, so specify raid as the sata mode.
With the latest intel drivers, a SSD will get passed the trim command to help with performance, so long as it is not part of a raid array.
Your two hard drives can be set up as raid-0.
That said, do you really have a app that will benefit from raid-0?
In most cases, the performance improvement that you see with synthetic sequential benchmarks do not show up in actual app performance.