Thinking about upgrading my airsoft gun...advice?

For accuracy, install a new hop-up unit, rubber etc, the lot, and a tight bore barrel, but seeing as it's a n AEG, I would not recommend a 6.01mm TBB, it would almost definitely jam whenever you used full auto, no matter what BBs you get, so get a 6.03mm TBB and use high quality BBs. I can't recommend BBs to you, as I'm searching for some high quality ones for myself to snipe with.