Never,ever build a sub with a Qtc higher than 0.7, and if you can stand the size, go for 0.5. The TC's have a peaky response that is overloading the room but not providing the upper bass needed for "slam". The Dayton's are providing a much flatter response and play louder where you need it.

You could port the Dayton's, but if you are not careful, you will wind up with the same boomy response as the TC's. A better bet would be to reduce the volume of the boxes until you get to a Qtc no higher than 0.7 -- just throw some junk in -- wood blocks, bricks, Styrofoam. Avoid the urge to get a ported max flat alignment.

Something that you need to remember is that efficiency equates to large box size. If you can stand 9ft^3 boxes, maybe you can stand twice that. Use two drivers a side. Also, have you considered manifold mounted IB's? Now THAT will give you some REAL bass!

Bob