I am building a setup which is close to yours.
For the bass enclosure I am using a vifa 10 inch woofer with an electronic 24dB crossover at 150Hz.Now, I am looking for a full range drive unit and was thinking about the Fostex FE166E.
How do the Fostex sounds?
Try building an electronic crossover, it will give a better performance than a passive one, I built the one that Rod Elliot designed.
http://sound.westhost.com/index.html
Yehuda.