Looks like you are on the right track. But assuming the card will work isn't the way to go. Call LaCie and ask. Sonnet also makes controller cards, and it might be good to go with them than mixing and matching too much. Limit the amount of vendors you need to call if something goes wrong.
Or, if this is over you head and you want something that works, go with www.caldigit.com solutions. Everything from one company and it works and works great.
I built my own SATA Raid using a PC case, but I did a lot of research first. First stop was www.hdforindies.com...read the FAQ. Also go to www.macgurus.com and read about rolling your own.
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