Just so you know, I used Kappa 15lf's in my pair as well, and I'm quite happy with them. A bit of midbass boominess, however that likely has more to do with the bracing situation rather than the driver itself.

I don't recall the exact alignment I used anymore, but it was something like 2.2 cubic feet (after displacement) with a 4"x10" port, with around a pound of polyfill in the chamber.

Adam