Need help choosing gaming barebone laptop

Need help dont know much between the difference in laptops.
Now each laptop i will be buying
-intel 5300 wifi
-Intel Core 2 duo T9400 2.53GHZ 6mb/L2 Cache 1066 FSB bus
-4gb of ddr2/ddr3 ram
-200gb 7200rpm hard drive

now for barebone laptops
MSI MS-1651 ID2 (GT628)
resolution 1680x1050
video card is 1gb nVIDIA GTS 160M
uses ddr3 ram 1066mhz which is gonna cost me $850

other barebone is
MS-1651
resolution 1280x800
video card 512mb 9600m GT DDR3
uses ddr2 ram 800mhz cost me $500-550

Now my question is.. Is it worth $300-400 to go with the new msi ms-1651 comparing to the old one. The most intense gaming graphics i do is left 4 dead and tf2 and the only game im thinking of playing is the new cs and of course diablo 3.