well..i went ahead and got the Level 4.

And about the BTL, i would love to have one. But i was buying used, so if was a little out of my price range.

Another thing that i guess just slipped my mind through this whole thing is that the level 4 has level 5 coils if that means anything in terms of spl and sq.

Just a gimmick bro

now you're responding like you claimed others were to you.

It's a never ending cycle...

I don't know much about DC subwoofers specifically, but a coil change could potentially affect Qts and Fs which will change various aspects of the drivers performance and enclosure requirements.