A simple repaint can go really far. I dry brushed black paint for weathering and used scraps of foam to "chip" paint from areas of high wear on the armor, such as the shoulders, backpack, chest, etc.

Scuff marks and such added where appropriate as well.

Custom versions of the DC-17M were also hand assembled and hand painted for this custom. I have all 3 - rifle, sniper, and (not pictured here) grenade launcher.