avus17:So BL2 yes or no?
Not quite being aware of how low 8000's can go in practise, or how good a sub BL2 exactly is, I'd still say yes, providing that the cutoffs and phase can be matched. Few if any full range speakers can reach subsonic frequencies, much less cleanly, and subwoofer's whole concept is to provide very low bass and true subsonic range. My Pentas and 5000 panels are both matched with Sunfire True Subwoofers (Signature) and even though most would think the pair of JMlabs I have in my basement listening room are close to defining the word "high" in high-end audio, they still benefit immensely from well-matched SVS Ultra subs.
It's not only about what you hear, it's what you feel in your whole body, too. Listening to high-quality recordings like selected top classical music recordings from Decca, Deutsche Grammophon or Virgin Veritas reveals the difference very easily, but even many of your favourite tracks "open up" when you have a properly set up subwoofer to compliment the sound of speakers.
A word of warning: subwoofers are by far the most abused and misused pieces of audio equipment in the world. They have a bad name as juvenile boomboxes, which is exactly what they are unless they're set up correctly. They're not about more oompah-oompah-bass, they're extensions to the low-end frequency response of speakers. Getting placement, cutoff, level and phase just right isn't easy but well worth the effort. There's a real reason why they're called SUBwoofers.
Go for it.
ps. For movies, tactile transducers take the whole concept of subsonic one step further. Good ones can go down to 1Hz. Haven't experimented with linear actuators yet, though...