I would advise against this, primarily because laptops are very finely calibrated machines. The power bricks and thermal systems are tuned specifically for the hardware that came with the unit.
So even assuming you could find a better video card to put into the unit, it could easily require more power than your AC adapter is capable of providing causing problems; or it will generate more heat than the fans in the unit are capable of expelling also causing problems.
Hmm, that video does give me pause. While I can probably pull it off, I would rather not risk it and just gift my current laptop to a family member or friend in need and upgrade. Thank you for the feedback.
Sorry. I was roaming the internet for an upgrade for my m17x r2 where I have stumbled upon this thread. (I am also kinda high...) But the dude isn't asking for ways to make his computer the same. He's looking for ways to make his computer more awesome then a Aleinware computer already is.
I say, my friend, that you should hit that bitch up with a second HD5870 and listen to that powerhouse purr.