Meanwhile, I took my sweet time and took the non-lethal route on every first mission runs in MGS V. I ended up getting FOXHOUND early in the game because of the way I do my missions since MGS 3, and S-ranked single missions in Peace Walker. I figured out a technique in taking the manned vehicles in side-ops and missions that I can take on a convoy without a single kill.
My advice? As soon as you see the legendary gunsmith side ops line, get to it. The weapon investments get more valuable for doing so.