I have finally decided on the alignment Im going for on my first DIY sub project. I picked the Adire Alignment. I definetly am using the Tempest. Anyway, the design calls for (2) 3 inch, flared ports on the bottom of the cabinet along with the driver. I would like to use (2) 4 inch ports. Im assuming Id get a nice reduction in compression, if it would occur in the first place. Can I expect this? Lets say I would get a worthwhile improvement, how long would the ports have to be now? They are originally about 11 inches long, tuned to approximatly 15hz. Second, would the 4" ports fit on the bottom? The space is pretty tight on the bottom. I guess I could just modify the schematics a little to fit the ports. Anyone know if they can help?