I post over @ F150online.com sometimes and sounds like you've been through a few different setups already.
Have you tried a ported setup yet? With the space you have available I think a single 12 in ~2ft^3 tuned in the low 30s would work perfect. You'd have as much output as two 12s sealed, maybe perceivable more since you'll have better low-end response.
Have you tried a ported setup yet? With the space you have available I think a single 12 in ~2ft^3 tuned in the low 30s would work perfect. You'd have as much output as two 12s sealed, maybe perceivable more since you'll have better low-end response.