desmond0806 wrote:
Does g53sx support intel 6300 or bigfootkiller 1103?

It "supports" any card with a working Windows 7 driver.

If you're asking whether those 3x3 cards will attain their top speed, that's not a function of the computer. It's a function of the network that your router broadcasts. If you are using the typical single-stream or dual-stream router that most users do, that is the network you get. It tops out at 300Mbps, and it only requires the two existing antennas. If you were to use a 3x3 router that actually broadcasts a 450Mbps network, you would need one of these 3x3 cards, plus you would need to add a third antenna to take full advantage of the network's capabilities.

In practice, BTW, few wireless networks operate at their maximum speed very often, and of course, faster wireless networks have no impact on internet speed or online performance whatsoever.