Hee heeIf you do anything like swapping CPU's your warranty will go out of the window - and considering you want the 3 year warranty its a foolish thing to do
Make up your mind first and get rid of all this silliness...Once you get your laptop you are not going to touch it until you get past the warranty period.
The 8887 is also a nice laptop and not as heavy as it looks. I have lifted the 5660, 5670 and 8887 and was honestly surprised that the 8887 was not ALL that heavy.
The 5670 will top out at 10 Lbs. The 8887 at 13 Lbs.
You cant go wrong with either laptop but if you are interested in playing games then stick with the 5670. It has the better screen and the 8887 screen has some ghosting problems which are not visible unless you play games...