Great i don't expect the prefab box i bought to last me long then lol. Anyways if i build the custom double chamber box for the two 15 btls that are each getting powered by a hifonics brutus BXI2008D what kind of numbers (DB) can i expect to get assuming each sub is getting 2000 watts at 1 ohm and the box is tuned to 35 hrtz. Oh and this will be in a Ford Excursion if that helps any.