Just to ask. Is it heresy to replace drivers in an enclosed speaker cabinet with an open baffle speaker such as the Lii 12 inch? I'm guessing it defeats some of the design, especially if its a 3-way with crossovers to filter the frequency. 
You can use some Lii Woofer or W12 in a big BR box with a suited Litrage volume.
The FR F12 You can not use as Woofer, it will sound strange and small power handling.