Well there are a few YouTube Videos that go over all the changes they have made with the E6 model.
Vickers Tactical
I know that LAV is full of himself but it's a great overview of the improvements.
Machinegun Mike Part 1
Machinegun Mike Part 2
now MG Mike is a channel that has lots of "cool" firearms and he talks about their history. He actually has a AKMSU clone that is 100% accurate to the original.
This last one is not a single video but a channel. It's dedicated to the M60 Machinegun. Some of the posts can be applied to other weapons systems. His "Predator Pack" is something I could see people in TW2K making.
M60 Machinegun Channel