Hello,
You have to remember that laptops have VERY limited space. So to try and upgrade from the 8700 to the 8800 in SLi would be very space consuming. Not to mention the heat factor brought on by this.
To get a new CPU might require a new mobo which is not easy to isntall. RAM on most laptops now a days are easily replaced with just the removal of 1 panel on the back.
Also have to remember that laptops use very think and easily breakable ribbon cables about the thickines of construction paper. Opening up the laptop to work on the insides too much could result in more damage than you know.
It is much harder to do these types of things with laptops. That is why people tend to buy the best one possible then run it till they cant no more and buy a new one. Upgrades for a laptop are much more expensive.
Cheers,
Mak