What are the weapons you guys use, and what's the config?
For me, I use standard weps, AK (only trigger mod, mods for 30-days weps so expensive!), sniper rifle, 1-week bullpup (full modif), and all but sniper rifle use the frag 'nade you bought at the shop (sniper without nade: reduced WT by 90 at least). That frag power sia, higher power, wider AoE!
Apparently, the mods price for short-term weapons are cheaper.