one factor: that rockford might be too much for the single kicker. i would keep the volume down respectively until you can get the other sub. what year is that comp? depending, you might be able to rub them both. it's not great, and might not sound right, but it's not like it won't work. if it is a 90's comp, i would be concerned about the cone being damage, but one from the past decade should hold up okay. also, if the box is shared chamber, and you only run the one cvr, it will shred the subs (both)