Ordering my m15x today depending on what you think..

Im in a rush to order the m15x because with the upgrades I'm adding it comes out to be right under $2050. When I do this online. But with same upgrades ordering over the phone it cones out to be around $1799. Only thing stopping me is the extra $100 for the Ati 5850. Witch will be around $1900. I'm at a budget of $1850 to spend. So I'm able to get the 1gb Ati 5730 I think it is with comes out to be $1799.

But if I wait untill next Friday I'm able to get the ati 5850 because payday! But then I have to wait alot longer to get the system in. Main reason I'm rushing is because the Dell sales rep says the special promotion might not be there by next Friday so if not then i'm stuff out of luck.

Im just wanting to know should I go with the Ati 5730 for now then later just buy a graphics card and instal? Or should I just wait?
Im just scared that the sales rep is right about having to take apart alot of crap to switch out the graphics card. But if this graphics card will be good for playing games like battlefield bad company 2 then I'd order today!! I've just never used the 5730 that's why I need your opinion! I have no problem with upgrading later I just don't know if alienware made there system with easy access of upgrading on our own. Please if you have any advice let me know I'd appreciate it.