I'm not sure a single 12 will give you the output you want. From everything I've read, a single 15 is enough for SQ guys, but SPL lovers need at least two 15s or more.
Given those two drivers, the W7 reportedly works great IB, but I would still give the edge to the FI since it is specifically designed for that application and it has excellent reviews. Also take a look at AE SBP12 and SBP15. Supposedly one of the best IB drivers. Those however have a 4-6 week lead time.
Mobridge DA2 > JBL MS-8 > JL Audio HD600/4 > (3) Hybrid Audio L3SE & (2) Rainbow Cal25; JL Audio HD900/5 > (2) Morel HCW-10 & (1) AE SBP15