G&G stock hop rubbers are good. I wouldn't go upgrading it until you have put at least 10K BB's through the gun. It's only then you will know if it needs upgrading or not.
The hop unit I wouldn't touch. If the one you are using can shoot and hop 0.2's then that is all you need for cqb. Dense woodland that might change as you may find you want to lift heavier bb's like 0.3's to beat cover.
Inner barrel again I wouldn't touch for CQB.
It boils down to basics, If you are playing cqb and the gun is working at the ranges you shoot at, hitting targets, and lifting bb's then there is nothing more you need to do to it to make it work better. Upgrades are generally done because of 2 things, you want more consistency at range, or you want to run with a ROF so high that everything needs locking down hard. Upgrading for the sake of upgrading is the single fastest way of making a good stock gun shoot badly. Leave it alone until you need to upgrade.