Yeah, that was my thought after looking harder as well...If the cabinet is ported I would stick with the intended driver that is being used. If you swap in a HST of any size it will most likely have the port chuffing a LOT if ever pushed to Xmax. Better to design from the ground up with the driver.
Plus my wife would like smaller subs much better since they will be easier on the eyes and easier to hide..... and then I could likely do more than 1.... maybe 3 hehehe..
So at this point just wondering if the WinISD files are out there yet so I can do some modeling for my own curiosity.