I want to upgrade my D boys Scar L. Unfortunately I'm new to gun building and I've taken the gearbox apart cleaned and regreased it. I have 200-300 dollar price limit. This will be something I do over time and would like to know what I should upgrade first. My fps limit is 400 and i would like to keep it hitting that hard. I also would loke a lot of accuracy. I don't care about rof.