I don't think different room correction will solve his problem or needs. JBL pro gear will thump your chest.My guess is you want >100dB SPL between 50-100hz to really feel the bass. In a car this is pretty easy to achieve, you also experience more pressurization than anything since it's a small space. On paper the 18" ultimaxes are also more than capable of this, looks like they can do up to 118dB or so in-room, so the question is whether you are actually getting the best from the subs or not.
Most likely the lack of chest thump is due to room interactions... bass is notoriously difficult to get even SPL throughout the room. You will want to tackle that with placement, lots of measuring, DSP, and possibly 2 more subs.
As for the overall sound quality, you can probably get pretty far with DSP on the mains as well. My advice would be to look at swapping the receiver for one that has Dirac or Trinnov or something?