but didn't u know... the more drive u put into a RAID 0 array, the higher disk-failure rate becomes........
vernong1992 is correct. Personally I think it would be a waste of money that could be used elsewhere, but if you are deadset on 3 hds than you would probably be better off getting 4 and going with a RAID 0+1 configuration. That is a tad bit overkill IMO also but it provides the speed and security of both arrays.