I have never heard of RAID rendering a drive bunk. All it would do is increase the HDD activity on that disk, but certainly not increase it's chance of failure. If you got a bunk drive to begin with, maybe it would increase the rate of failure, but not by putting it into RAID.
Chank, we're not talking math here man.
in theory, two drives in RAID 0 should be double the time. But that is theory, and theory is never actually true to life, which is why it is theory and not fact.
But RAID increasing the rate of failure for Raptors only? C'mon...