Does anyone know if it's possible to fit RIS to a G&G RK47, extend barrels on G&G M4's and AK/RK's, where I can find the cheapest batteries and chargers for G&G's, what Batteries will fit inside the RK stock (that's where i'm guessing it goes) and what will fit in the combat machine stock and what to charge them with, and where to find the cheapest G&G products that I can get 2 toned.