Looking to buy a new laptop

Hello all,

I am looking to buy a desktop replacer. I need to replace my old pc and want to go for something more mobile.

The Dell Inspiron 9400 caught my eye, I can basicly get it with everything I want. Except for one thing, its being sold (on the dutch site) with a: 256MB DDR ATI® MOBILITY™ RADEON® X1400 graphics card, PCI-Express x16

I however want to get a geforce go 7800 GTX. Is it possible to remove the Radeon and just buy a geforce 7800 somewhere else and slot that in instead?

I am pretty new to laptops so I am unfamiliar with the possibilities of tinkering with them.

Is it possible to put in a geforce 7800 in a dell Inspiron 9400 and where can buy a seperate geforce 7800 grahphics card?

Yeah I have, they are very limited in providing services regarding other then video cards they offer in the systems.

However if I wanted a good gaming laptop that can also do other things well
They suggest the precision M90.

What would be better?

-The Dell Precision M90 with Intel Dual Core and a NVIDIA® Quadro® FX 2500M with 512MB

Or:

-The Dell XPS M170 with Intel M and a NVIDIA Geforce 7800 GTX with 256MB