VelociRaptor on alienware?

I don't believe so, as laptops like that use a smaller sized HDD. A V. Raptor, with its plastic encasing is a 3.5'' drive, i.e. it will not fit.

Come to think of it, if you are looking for more performance and do not need that much space, invest in a SSD for your laptop. Most, even cheap ones are faster than the V. Raptor in many respects.