Extra HDD

256GB mSATA SSD Boot + 1TB 5400RPM SATA 6Gb/s

This is what the confirmation E-mail says about the hard drive(s) on my alienware 18. Basically my question is: I know there are two HDD slots on my alienware 18, but but i'm not sure if both are in use as of now. Are there some kind of hybrid soloution? Or is this the kind of small ssd's ive seen around? I am abroad now where SSD's are considerably cheaper than back home and i'm thinking about buying an 1TB SSD. So basically.. Does anyone have any idea if i am able to fit one extra, or do i have to remove one to be able to fit the 1 TB ssd?
On the Alienware 18 you have lots of options. There is a Msata Slot that could house a 1tb Msata. The Hard drive bay has a casing that will house two SSD Hard drives. Here you could install 2 1tb ssds. That is a total possible 3tbs right off the bat in a stock system. Further more, you could remove the cd rom drive bay and buy the drive adapter and house two more in this section. (This is how some systems were built with 4x256gb SSD's) If you went this route you could install two more 1tb SSD's and have a total of 5tb's in the Alienware 18 system.