The Haxo subs are just a rebadged version of the Crystal mobilesound subs. The Crystal CMP=Haxo LXU, the Compx2=LXO. Slightly different cosmetically but still the same beast...great sounding beast I might add. I have owned a handful of Audiomobile subs and absolutely love underhung designs. I have also heard quite a few CMPs and they sounded great as well. Elemental Designs was selling Haxo subs for a while including the LXU(underhung) versions. They can also custom build subs using Haxo/Crystal parts. I have inquired about having my two Audiomobile Mass underhung motors rebuilt as a pair of underhung 15s using Haxo baskets, cones and soft parts. They said they could do it and at about $150 each including shipping. I say give ED a call and have them rebuild them for you and have yourself one hell of a pair of subs for far less $$ than anything esle out there. You will be hard pressed to find a pair of subs with that kind of SQ and output for the $$ you will have to spend to get those rebuilt. The only other designs out there that are as linear would be the TC sounds developed LMS drivers(used by a handful of audio companies) and the BL^2 designs used by a handful as well. Both of those options would almost certainly cost more. Congrats on a good deal.