General [Integrated] SATA & RAID Query

Greetings. Having found no existing threads on this issue...

I understand RAID. I have used several arrays over the last few years; on
PCI and integrated. When I built this system, I began with a single SATA
drive, but I've since added a second identical drive and mirrored them.
(Would've preferred striping, but wanted to avoid the re-install) Anyway, I
find myself wondering about a couple of things:

Ultimately, I would like to remove the mirrored pair of 80GB drives, and
revert to a striped pair of 37GB Raptors. But I can't afford 2 Raptors
right now, so I intend to run on just one for awhile. Toward that end, I
realize that I can remove ONE of the drives, and the other one should run
smoothly. But at start-up, the RAID BIOS will always tell me that the array
is damaged. So, can I *delete* the array with no data loss on the orig
drive?

Next...with PATA drives, when you want to replace a drive, you can use free
migration s/w to clone the existing drive to the replacement and away you
go. Is there migration s/w for SATA drives? I can't imagine that the
existing migration utilities will work with SATA drives, but it would be
awfully handy if I could revert to a single drive (see above) and then
migrate it to a single Raptor [so that I can remove the other non-Raptor].

Thank you kindly for your assistance.
Ron