Air volume size for JL Audio C3-650

[Maltby6]

Yeah, these aren't big subs, but I'm designing enclosures for my 6 1/2 inch JL Audio speakers. They are going in a Toyota Landcruiser FJ40 and will be attached to the rear roll bar but sitting on the fender well. Space is not an issue. They will be powered by a JL Audio vx800 and playing all types of music including rap. I was thinking sealed but open to suggestions. I'll be running full component with the passive crossover as I have another set of C3-600s in the doors, infinity kappas in the dash and tweets up high. I'm just out of channels.

I've looked everywhere for the volume recommendations on these but they just don't get the same love as the big subs.