The Evo Firecracker Bugs described are a bit more powerful than how I had them for v1. With 2" and 3xD6 like a Chem grenade, the Arachnid player's option to detonate, and 7 in a unit, you're looking at 21xD6 dice at 10 points per model. That's more dice than Warrior Bugs and a cheaper unit.
The SSTv1 ones I described were a bit more toned down. The Arachnid player can't control when they explode. They automatically do when an enemy gets within 1". They also are only a frag grenade in effect, 1" and D10.