I dont think the internals neccessarily need to be overhauled due to the abundance of steel components. However i've read that this thing likes to shatter bb's and mash them into the hop up creating a lovely mess to pick out of your gun. The RA-Tech complete steel carrier and bolt system combined with their enhanced hop is supposed to apparnetly fix all feeding issues the gun has. I have those parts on order as well and will be the first upgrade that goes into my gun. Beyond that, I couldnt imagine what else in terms of upgrades is even necessary for the gun, I may even downgrade it some how in order to be able to keep it under 350 FPS for indoor use.