Alienware m14x Processors and RAM?

I am thinking of getting the m14x but the price is a little high for me. What i want to know is, do i absolutely have to have the 3.3Ghz processor or will the 2.9Ghz be enough? Also should i upgrade the RAM to 6GB or 8GB or will 4GB be enough to play pretty much all games smoothly? I have already decided on getting the 3GB video card so I guess that should improve the performance. I really don't want to spend $1600+ on a new laptop, but if I have to to be able to play games flawlessly I will.