i'm not sure about the difference, you might wanna compare them side by side.
for processor/cpu, it's better to get 3840qm. previously there was a report that a 55-watt extreme cpu didn't work well. also, the stock cpu heat sink is not meant for high-end cpu.
chipset change is kind of impossible, but i am not sure.
use ddr3 1600MHZ 1.5v for maximum compatibility. you can run full 4x8gb with that. anything higher might not run well.