Prolly biggest thing ya can do for a noticeable difference would be get a lighter hopper (Like a pinokio or Emprie Z2). Other than that ya could get a lighter barrel (Deadly Winds makes freak bored carbone fibur barrels) and a smaller tank (hard cause mags like there AIR).
That being said i personally feel the best thing is to balance your gun out. Idealy i like the gun to ballence out on the back of the grip frame. So i mess with a few things to achive this. This has the effect of making the gun at least to me feel lighter.
Personally i run a similare setup only mines a AM/MM rail and just a Lapco barrel and a X-Valve. I run a Ninja Dura 77ci tank and a Z2 hopper. It balances out great points well and does not feel weighty at all i love it.
AGD 68 Automag, Azodin KP2, Tippmann Pro/Carbine & SL-68II, Sheridan PGP2