I use an engineering chassis just because no one else does. I forget which specific chassis, but I rock a magnet grenade launcher, razor of the gods, and a massive sniper turret.
You assault clowns can keep your six weapon slots while I set up nasty kill zones with my sniper/dampening combos. What are Volt Droppers again? It's been a while since they've survived longer than a couple of seconds when I'm playing.