All you have to do to make the explosion bigger is to go to pctl (Particle System) tag and go to for example scorpion explosion and change the radius for the explosion in the meta editor to for example 20.
To make the damage just go to jpt tag and go to the desired explosion and change the radius to what you like.
You can change the colour in the ligh tag and more. So you dont really need to import any explosion effects because you can create one. I did it and it works.
One thing i would like that you experiment with other stuff because the explosion might still not look amazing.
Good Luck
