Re: Ram questions
I wouldn't upgrade to that at all, unless you're benchmarking, or running a server; you'll get very little, if ANYTHING, out of games at 16GB, although it will look nice on paper.
"4x 4Gb's will work fine - but personally go for the 2x 8Gb's and put them in Dual Channel." - I second this.
And as Jake said, make sure the modules are identical (same size, speed, and probably brand) to properly utilise dual mode.