Sonnie, this is very exciting!
I do have a question however. In most cases, doesn't an IB allignment have lesser Xmax utilization than typical sealed or vented allignment due to the relatively low stress on each driver? You'll have so much cone area with 15" subs and effeciency due to large Vb of an IB enclosure that you'll probably barely use all 23.4mm of Xmax the SS Rl-p 15 has to offer in theory? I could be completely wrong but this is my current understanding of IB,nor do I know if the RL-P 15 is considered a low Qts driver. Also with the low Q associated with IB you'll probably not get slow bass at all! You'll be in for a treat indeed.
Edit: look how flat you've gotten your Fr with just a few filters...you're a pro indeed
